title: Turner syndrome

text: Growth delay in Turner syndrome does not begin at birth; most neonates with the condition have a birth weight in the lower end of the normal range. Height begins to lag in toddlerhood, with a delayed growth velocity becoming apparent as early as 18 months. When girls with Turner syndrome begin school, their height is usually still not remarkably unusual; marked short stature becomes obvious in mid-childhood. In undiagnosed preadolescents and adolescents, growth delay may be mistaken for a side effect of delayed puberty and improperly treated. Short stature in Turner syndrome and its counterpoint, tall stature in sex chromosome polysomy conditions such as Klinefelter syndrome, XYY syndrome, and trisomy X, is caused by the short-stature homeobox gene on the X and Y chromosomes. The absence of a copy of the "SHOX" gene in Turner's inhibits skeletal growth, resulting both in overall short stature and in a distinctive pattern of skeletal malformations including micrognathia (small chin), cubitus valgus (abnormal forearm angles), and short fingers.


title: Turner syndrome

text: When Turner syndrome is diagnosed in early life, growth hormone therapy can decrease the degree of short stature. The use of growth hormone therapy in Turner's originated from a series of studies in the 1980s finding it to substantially increase the height of treated girls, compared to prior adult height predictions and Turner's growth charts; treatment with human growth hormone appears to increase expected adult height by approximately from an otherwise expected norm of –. In some cases oxandrolone, a steroid with a relatively mild masculinizing effect, may be used alongside growth hormone. The addition of oxandrolone to a Turner's treatment regimen adds around to the final height. Oxandrolone is used particularly often in girls diagnosed later in their growth period, due to the reduced impact of growth hormone alone in this population. However, oxandrolone use runs the risk of delayed breast development, voice deepening, increased body hair, or clitoromegaly. The effects of growth hormone therapy are at their strongest during the first year of treatment and taper off over time.


title: Turner syndrome

text: In addition to short stature, Turner syndrome is associated with a number of characteristic physical features. These include a webbed neck, a low hairline, a small chin and jaw, a high-arched palate, and a broad chest with wide-spaced nipples. Lymphedema (swelling) of the hands and feet is common at birth and sometimes persistent throughout the lifespan. Some Turner's stigmata, such as cubitus valgus and shortened fingers, are related to "SHOX" gene dosage effects.


title: Turner syndrome

text: A number of the external manifestations of Turner syndrome are focused on the limbs, hands, and feet. Lymphedema at birth is one of the classic features of the syndrome; though it often resolves during toddlerhood, recurrence in later life is frequent, often without apparent cause. Cases where the retained X chromosome was inherited from the mother more often experience lymphedema than those where it was from the father. As a consequence of lymphedema's effects on nail anatomy, females with Turner syndrome frequently have small hypoplastic nails. Shortened metacarpal bones, particularly the fourth metacarpal, are a frequent finding. The body shape of individuals with Turner syndrome is frequently quite broad and stocky, as the growth deficiency is more pronounced in the length of bones than in their width. Scoliosis is common in Turner syndrome, and is seen in 40% of girls without growth hormone treatment.


title: Turner syndrome

text: Facial features associated with Turner syndrome include prominent ears, a low hairline, a webbed neck, a small chin with dental malocclusion, and downslanting palpebral fissures (the opening between the eyelids). These are thought to be related to lymphedema during the fetal period, specifically to the presence and resorption of excess fluids in the head and neck region. Neck webbing is a particularly distinctive trait of Turner syndrome, leading to many neonatal diagnoses. The underlying etiology of neck webbing is related to prenatal blood flow issues, and even in populations without Turner's has broad health consequences; the rate of congenital heart disease in webbed neck is 150-fold higher than in the general population, while the feature is also associated with reduced height and minor developmental impairments. Some women with Turner syndrome have premature facial wrinkling. Acne is less common in teenage girls and women with Turner syndrome, though the reasons why are unclear.


title: Turner syndrome

text: Other physical features connected to the condition include long eyelashes, sometimes including an additional set of eyelashes, and unusual dermatoglyphics (fingerprints). Some women with Turner's report being unable to create fingerprint passwords due to hypoplastic dermatoglyphics. Unusual dermatoglyphics are common to chromosome anomalies and in the case of Turner's may be a consequence of fetal lymphedema. Keloid scars, or raised hypertrophic scars growing beyond the boundaries of the original wound, are potentially associated with Turner syndrome; however, the association is underresearched. Though traditional medical counselling on the topic urges conservatism about elective procedures such as ear piercing due to the risk of severe scarring, the actual consequences are unclear. Keloids in Turner syndrome are particularly frequent following surgical procedures to reduce neck webbing. Turner syndrome has been associated with unusual patterns of hair growth, such as patches of short and long hair. Armpit and pubic hair is often sparse, while arm and leg hair is often thick. Though armpit hair is reduced in amount and thickness, the pattern in which it is implanted in the skin is as in men, rather than as in women.


title: Turner syndrome

text: Approximately half of individuals with Turner syndrome have congenital heart defects. CHDs associated with Turner syndrome include bicuspid aortic valves (30%), coarctation of the aorta (15%), and abnormalities of the arteries in the head and neck. A rare but potentially fatal complication of heart defects in Turner syndrome is aortic dissection, where the inner layer of the aorta tears open. Aortic dissection is six times as common in females with Turner syndrome as the general population and accounts for 8% of all deaths in the syndrome. The risk is substantially increased for individuals with bicuspid aortic valves, who make up 95% of patients with aortic dissection compared to 30% of all Turner's patients, and coarctation of the aorta, who make up 90% and 15% respectively.


title: Turner syndrome

text: Coronary artery disease onsets earlier in life in women with Turner syndrome compared to controls, and mortality from cardiac events is increased. This is thought to be in part a function of the relationship between Turner syndrome and obesity; women with Turner syndrome have a higher percentage of body fat for their weight than control women, and their short stature makes weight control more difficult. Though coronary artery disease is frequently thought a disease of older adults, young women with Turner syndrome are more likely to develop the disease than their 46,XX peers. Treatment recommendations for women with Turner syndrome and coronary artery disease are as in the general population, but as Turner's increases the risk of type 2 diabetes, women with insulin resistance must weigh up the benefits of prophylactic or early statin treatment with the risk of diabetes.


title: Turner syndrome

text: Turner syndrome is associated with a broad variety of health considerations, such as liver and kidney issues, obesity, diabetes, and hypertension. Liver dysfunction is common in women with Turner syndrome, with 50%–80% having elevated liver enzymes. Non-alcoholic fatty liver disease is increased in prevalence in Turner syndrome, likely related in part to both conditions' associations with obesity. Hepatic vascular diseases are also seen in the syndrome as an aspect of Turner syndrome's broader vascular and cardiac impacts. Primary biliary cholangitis is more common in 45,X0 than 46,XX women. An unclear association exists between estrogen replacement therapy and liver dysfunction in Turner syndrome; some studies imply estrogen therapy worsens such conditions, while others imply improvement.


title: Turner syndrome

text: Kidney issues, such as horseshoe kidney, are sometimes observed in Turner syndrome. Horseshoe kidney, where the kidneys are fused together in a U-shape, occurs in around 10% of Turner's cases compared to less than 0.5% of the general population. A missing kidney is observed in as many as 5% of individuals with Turner syndrome, compared to around 0.1% of the population. A duplicated ureter, where two ureters drain a single kidney, occurs in as much as 20%–30% of the Turner syndrome population. Kidney malformations in Turner syndrome may be more common in mosaicism than in the full 45,X0 karyotype. Serious complications of the kidney anomalies associated with Turner syndrome are rare, although there is some risk of issues such as obstructive uropathy, where the flow of urine from the kidneys is blocked.


title: Turner syndrome

text: Women with Turner syndrome are more likely than average to have high blood pressure; as many as 60% of women with the condition are hypertensive. Isolated diastolic hypertension often precedes systolic hypertension in the condition and may develop at a young age. Treatments for hypertension in Turner syndrome are as in the general population.


title: Turner syndrome

text: Approximately 25%–80% of women with Turner syndrome have some level of insulin resistance, and a minority develop type 2 diabetes. The risk of diabetes in Turner syndrome varies by karyotype and appears to be raised by specific deletions of the short arm of the X chromosome (Xp). One study found that while a relatively low 9% of women with Xq (long arm) deletions had type 2 diabetes, 18% of those with full 45,X0 karyotypes did, as well as 23% with Xp deletions. 43% of women with isochromosome Xq, who both lacked the short arm and had an additional copy of the long arm, developed type 2 diabetes. Though part of the diabetes risk in Turner syndrome is a function of weight control, some is independent; age- and weight-matched women with non-Turner's ovarian failure have a lower diabetes risk than in Turner syndrome. Growth hormone treatment plays an unclear role in diabetes risk, as does estrogen supplementation.


title: Turner syndrome

text: The association between Turner syndrome and other diseases, such as cancer, is unclear. Overall, women with Turner syndrome do not appear more likely to develop cancer than women with 46,XX karyotypes, but the specific pattern of what cancers are highest risk seems to differ. The risk of breast cancer appears lower in Turner's than in control women, perhaps due to decreased levels of estrogen. Neuroblastoma, a cancer of infancy and early childhood, has been reported in girls with Turner syndrome. Tumours of the nervous system, both the central nervous system and the peripheral nervous system, are overrepresented amongst cancers in Turner syndrome. Furthermore, about 5.5% of Turner syndrome individuals have an extra, abnormal small supernumerary marker chromosome (sSMC) which consists of part of a Y chromosome. This partial Y chromosome-bearing sSMC may include the "SRY" gene located on the p arm of the Y chromosome at band 11.2 (notated as Yp11.2). This gene encodes the testis-determining factor protein (also known as sex-determining region Y protein). Turner syndrome individuals with this "SRY" gene-containing sSMC have a very real increased risk of developing gonadal tissue neoplasms such as gonadoblastomas and in situ seminomas (also termed dysgerminomas to indicate that this tumor has the pathology of the testicular tumor, seminoma, but develops in ovaries). In one study, 34 Turner syndrome girls without overt evidence of these tumors were found at preventative surgery to have a gonadoblastoma (7 cases), dysgerminoma (1 case), or non-specific "in situ" gonadal neoplasm (1 case). Turner syndrome girls with this sSMC otherwise have typical features of the Turner syndrome except for a minority who also have hirsutism and/or clitoral enlargement. Surgical removal of the gonads has been recommended to remove the threat of developing these sSMC-associated neoplasms. Tuner syndrome individuals with an sSMC that lacks the "SRY" gene are not at an increased risk of developing these cancers.


title: Turner syndrome

text: Hearing loss is common in Turner syndrome. Though at birth hearing is generally normal, chronic middle ear problems are frequent throughout childhood, which can cause permanent conductive hearing loss. In adulthood, sensorineural hearing loss occurs more often than in 46,XX women and at younger ages; though differing thresholds of hearing loss make it difficult to compare between studies, younger adult women with Turner syndrome are routinely found to have disproportionate rates of hearing issues, with sometimes up to half of women in their 20s and 30s having poor hearing. This hearing loss is progressive; at the age of 40, women with Turner syndrome have equivalent hearing loss to 46,XX women aged 60, on average. Cohort studies imply hearing loss may be more common in women who also have metabolic syndrome. The high prevalence of sensorineural hearing loss in Turner syndrome appears to be related to "SHOX" deficiency.


title: Turner syndrome

text: Ocular and visual disorders are also increased in prevalence in Turner syndrome. More than half of individuals with Turner syndrome have some form of eye disorder. This may be a consequence of shared genes on the X chromosome in both eye and ovary development. Nearly half of cases have hyperopia or myopia, usually mild. Strabismus, or misalignment of the eye, occurs in around one-fifth to one-third of girls with Turner syndrome. As with strabismus outside the Turner's context, it may be treated with glasses, patching, or surgical correction. Esotropia, where the eye turns inwards, is more common than exotropia, where it turns outwards. Ptosis, or a drooping eyelid, is a common facial manifestation of Turner syndrome; it usually has no appreciable impact on vision, but severe cases may limit visual range and require surgical correction. The rate of red-green colourblindness in Turner syndrome is 8%, the same as in men. This is due to red-green colourblindness being an X-linked recessive condition; in people with a single X chromosome, whether normal males or Turner females, only a single mutated X is necessary for symptoms. Red-green colourblindness may be underdiagnosed in the Turner context, as the rarity of the condition in females reduces the likelihood of screening, and practitioners may not connect that the karyotype of Turner syndrome increases the risk from the female baseline.


title: Turner syndrome

text: Women with Turner syndrome are two to three times as likely to develop autoimmune disorders as the general population. Specific autoimmune disorders linked to Turner syndrome include Hashimoto's disease, vitiligo, psoriasis and psoriatic arthritis, alopecia, and celiac disease. Inflammatory bowel disease is also common, while the prevalence of type 1 diabetes is unclear, though appears increased.


title: Turner syndrome

text: Thyroid disease is common in Turner syndrome. Hypothyroidism is prevalent; 30%–50% of women with Turner syndrome have Hashimoto's disease, where the thyroid gland is slowly destroyed by an autoimmune reaction. By age 50, half of women with Turner syndrome have subclinical or clinical hypothyroidism. Hyperthyroidism and Graves' disease are also increased in prevalence, though more modestly. The Turner's presentation of hyperthyroidism is as in the general population, while the presentation of hypothyroidism is often atypical, with a mild early presentation yet a more severe progression. Women with isochromosome Xq are more likely to develop autoimmune thyroid disease than women with other forms of Turner syndrome.


title: Turner syndrome

text: The risk of irritable bowel syndrome is increased around fivefold in Turner syndrome, and that of ulcerative colitis around fourfold. Celiac disease is also increased in prevalence, with around 4%–8% of Turner's patients having comorbid celiac disease compared to 0.5%–1% of the general population. Diagnosis of such conditions is difficult due to their nonspecific early symptoms. In the Turner's context, diagnosis may in particular be missed due to growth delay; such conditions cause growth delay and failure to thrive when they onset in childhood, but as girls with Turner syndrome already have such delay, symptoms may be overlooked and ascribed to the original condition.


title: Turner syndrome

text: Alopecia areata, or recurrent patchy hair loss, is three times as common in Turner syndrome as the general population. Alopecia in the Turner syndrome context is frequently treatment-resistant, also seen in other chromosome aneuploidies such as Down syndrome. Psoriasis is common in Turner syndrome, although the precise prevalence is unclear. Turner's psoriasis may be related to growth hormone treatment, as psoriasis as a side effect of such therapies has been reported in patients without the karyotype. Psoriasis may progress to psoriatic arthritis, and this progression may be more common in Turner syndrome. Vitiligo has been reported in conjunction with Turner syndrome, but the risk is unclear and may be a side effect of increased clinical attention to autoimmune disease in this population.


title: Turner syndrome

text: Puberty is delayed or absent in Turner syndrome. A 2019 literature review found that 13% of women with a 45,X0 karyotype could expect to experience spontaneous thelarche (breast development), while 9% would undergo spontaneous menarche (beginning of menstruation). These numbers were higher in women with mosaic Turner's; 63% with 45,X0/46,XX karyotypes experienced spontaneous thelarche and 39% spontaneous menarche, while 88% with 45,X0/47,XXX (the presence of a trisomy X cell line) experienced spontaneous thelarche and 66% spontaneous menarche. Unexpectedly, women with Y-chromosome cells also had increased rates of thelarche and menarche compared to the 45,X0 baseline, at 41% and 19%. However, few women with trisomy X or Y-chromosome cell lines were covered in the review, impeding extrapolation from these results. 6% of women with Turner syndrome have regular menstrual cycles; the rest experience primary or secondary amenorrhea or other menstrual dysfunction.


title: Turner syndrome

text: In girls with Turner syndrome who do not experience spontaneous puberty, exogenous estrogen is used to induce and maintain feminization. Estrogen replacement is recommended to begin at around age 11–12, although some parents prefer to delay the induction of puberty in girls with lower social and emotional preparedness. The dose of estrogen in induced puberty begins at 10% of adult estrogen levels and is steadily increased at six-month intervals, with a full adult dose attained two to three years after the beginning of treatment. Estrogen replacement may interfere with growth hormone therapy, due to the closing effects of estrogen on growth plates; individuals must weigh up their preferences for taller height versus greater feminization.


title: Turner syndrome

text: Women with Turner syndrome are infertile. Only 2%–5% are capable of pregnancy without fertility treatment, most with mosaic karyotypes. Early in gestation, fetuses with Turner syndrome have a normal number of gametes in their developing ovaries, but this starts decreasingly rapidly as early as 18 weeks of pregnancy; by birth, girls with the condition have markedly reduced follicular counts. Women with Turner syndrome who wish to raise families but are incapable of conception with their own oocytes have the options of adoption or of pregnancy with donor eggs; the latter has a comparable success rate to donor pregnancy in women with 46,XX karyotypes.


title: Turner syndrome

text: Usually, estrogen replacement therapy is used to spur the growth of secondary sexual characteristics at the time when puberty should onset. While very few women with Turner syndrome menstruate spontaneously, estrogen therapy requires a regular shedding of the uterine lining ("withdrawal bleeding") to prevent its overgrowth. Withdrawal bleeding can be induced monthly, like menstruation, or less often, usually every three months, if the patient desires. Estrogen therapy does not make a woman with nonfunctional ovaries fertile, but it plays an important role in assisted reproduction; the health of the uterus must be maintained with estrogen if an eligible woman with Turner Syndrome wishes to use IVF (using donated oocytes).


title: Turner syndrome

text: Especially in mosaic cases of Turner syndrome that contains Y-chromosome (e.g. 45,X/46,XY) due to the risk of development of ovarian malignancy (most common is gonadoblastoma) gonadectomy is recommended. Turner syndrome is characterized by primary amenorrhoea, premature ovarian failure (hypergonadotropic hypogonadism), streak gonads and infertility (however, technology (especially oocyte donation) provides the opportunity of pregnancy in these patients). Failure to develop secondary sex characteristics (sexual infantilism) is typical.


title: Turner syndrome

text: Individuals with Turner syndrome have normal intelligence. Verbal IQ is usually higher than performance IQ; one review of thirteen studies found an average verbal IQ of 101 compared to an average performance IQ of 89.


title: Turner syndrome

text: People with Turner syndrome have normal intelligence, and demonstrate relative strengths in verbal skills, but may exhibit weaker nonverbal skills – particularly in arithmetic, select visuospatial skills, and processing speed. Turner syndrome does not typically cause intellectual disability or impair cognition. However, learning difficulties are common among women with Turner syndrome, particularly a specific difficulty in perceiving spatial relationships, such as nonverbal learning disorder. This may also manifest itself as a difficulty with motor control or with mathematics. While it is not correctable, in most cases it does not cause difficulty in daily living. Most Turner syndrome patients are employed as adults and lead productive lives.


title: Turner syndrome

text: Also, a rare variety of Turner syndrome, known as "Ring-X Turner syndrome", has about a 60% association with intellectual disability. This variety accounts for around 2–4% of all Turner syndrome cases.


title: Turner syndrome

text: Social difficulties appear to be an area of vulnerability for young women. Counseling affected individuals and their families about the need to carefully develop social skills and relationships may prove useful in advancing social adaptation. Women with Turner syndrome may experience adverse psychosocial outcomes which can be improved through early intervention and the provision of appropriate psychological and psychiatric care. Genetic, hormonal, and medical problems associated with Turner syndrome are likely to affect psychosexual development of female adolescent patients, and thus influence their psychological functioning, behavior patterns, social interactions, and learning ability. Although Turner syndrome constitutes a chronic medical condition, with possible physical, social, and psychological complications in a woman's life, hormonal and estrogen replacement therapy, and assisted reproduction, are treatments that can be helpful for Turner syndrome patients and improve their quality of life. Research shows a possible association between age at diagnosis and increased substance use and depressive symptoms.


title: Turner syndrome

text: Despite the excellent postnatal prognosis, 99% of Turner syndrome conceptions are thought to end in miscarriage or stillbirth, and as many as 15% of all spontaneous abortions have the 45,X karyotype. Among cases that are detected by routine amniocentesis or chorionic villus sampling, one study found that the prevalence of Turner syndrome among tested pregnancies was 5.58 and 13.3 times higher, respectively, than among live neonates in a similar population.


title: Turner syndrome

text: Turner syndrome is caused by the absence of one complete or partial copy of the X chromosome in some or all the cells. The abnormal cells may have only one X (monosomy) (45,X) or they may be affected by one of several types of partial monosomy like a deletion of the short p arm of one X chromosome (46,X,del(Xp)) or the presence of an isochromosome with two q arms (46,X,i(Xq)) Turner syndrome has distinct features due to the lack of pseudoautosomal regions, which are typically spared from X-inactivation. In mosaic individuals, cells with X monosomy (45,X) may occur along with cells that are normal (46,XX), cells that have partial monosomies, or cells that have a Y chromosome (46,XY). The presence of mosaicism is estimated to be relatively common in affected individuals (67–90%).


title: Turner syndrome

text: The (46,X,i(Xq) isochromosome in the Turner syndrome is classified as an small supernumerary marker chromosome (sSMC). Two of the types of sSMCs in this syndrome contain parts of the genetic material from either an X or, much less frequently, Y chromosome and may or may not contain an "XIST" gene. In normal females, the "XIST" gene occurs on the X chromosome inherited from her mother but not on the X chromosome inherited from her father. The gene is not present on Y chromosomes and in normal females resides on and functions to inactivate many of the genes located on its own maternal but not the father's X chromosome. Turner syndrome females with (46,X,i(Xq) sSMC consisting of a partial X chromosome that does not contain the "XIST" gene express at least some of this sSMC's genetic material and therefore contain excesses of this material. In consequence, they have a more serious form of the Turner syndrome that ranges form moderately severe to extremely severe. The extremely severe cases have anencephaly (absence of a major portion of the brain, skull, and scalp), agenesis of the corpus callosum (lack of the thick tract of nerve fibers that connect the left and right cerebral hemispheres), and complex heart deformities. Individuals with Turner syndrome that have partial X chromosome containing(46,X,i(Xq) sSMCs that have the "XIST" gene do not express this sSMC's genetic material and do not have the more severe manifestations of the syndrome.


title: Turner syndrome

text: In the majority of cases where monosomy occurs, the X chromosome comes from the mother. This may be due to a nondisjunction in the father. Meiotic errors that lead to the production of X with p arm deletions or abnormal Y chromosomes are also mostly found in the father. Isochromosome X or ring chromosome X on the other hand are formed equally often by both parents. Overall, the functional X chromosome usually comes from the mother.


title: Turner syndrome

text: In most cases, Turner syndrome is a sporadic event, and for the parents of an individual with Turner syndrome the risk of recurrence is not increased for subsequent pregnancies. Rare exceptions may include the presence of a balanced translocation of the X chromosome in a parent, or where the mother has 45,X mosaicism restricted to her germ cells.


title: Turner syndrome

text: Usually, fetuses with Turner syndrome can be identified by abnormal ultrasound findings ("i.e.", heart defect, kidney abnormality, cystic hygroma, ascites). In a study of 19 European registries, 67.2% of prenatally diagnosed cases of Turner syndrome were detected by abnormalities on ultrasound. 69.1% of cases had one anomaly present, and 30.9% had two or more anomalies.


title: Turner syndrome

text: An increased risk of Turner syndrome may also be indicated by abnormal triple or quadruple maternal serum screen. The fetuses diagnosed through positive maternal serum screening are more often found to have a mosaic karyotype than those diagnosed based on ultrasonographic abnormalities, and conversely, those with mosaic karyotypes are less likely to have associated ultrasound abnormalities.


title: Turner syndrome

text: Turner syndrome can be diagnosed postnatally at any age. Often, it is diagnosed at birth due to heart problems, an unusually wide neck or swelling of the hands and feet. However, it is also common for it to go undiagnosed for several years, often until the girl reaches the age of puberty and fails to develop typically (the changes associated with puberty do not occur). In childhood, a short stature can be indicative of Turner syndrome.


title: Turner syndrome

text: A test called a karyotype, also known as a chromosome analysis, analyzes the chromosomal composition of the individual. This is the test of choice to diagnose Turner syndrome.


title: Turner syndrome

text: As a chromosomal condition, there is no cure for Turner syndrome. However, much can be done to minimize the symptoms. While most of the physical findings are harmless, significant medical problems can be associated with the syndrome. Most of these significant conditions are treatable with surgery and other therapies including hormonal therapy.


title: Turner syndrome

text: Approximately 99 percent of fetuses with Turner syndrome spontaneously terminate during the first trimester. Turner syndrome accounts for about 10 percent of the total number of spontaneous abortions in the United States.


title: Turner syndrome

text: The syndrome is named after Henry Turner, an endocrinologist from Illinois, who described it in 1938. In Europe, it is often called "Ullrich–Turner syndrome" or "Bonnevie–Ullrich–Turner syndrome" to acknowledge that earlier cases had also been described by European doctors Kristine Bonnevie and Otto Ullrich. In Russian and USSR literature, it is called "Shereshevsky–Turner syndrome" to acknowledge that the condition was first described as hereditary in 1925 by the Soviet endocrinologist , who believed that it was due to the underdevelopment of the gonads and the anterior pituitary gland and was combined with congenital malformations of internal development.


title: Turner syndrome

text: The first published report of a female with a 45,X karyotype was in 1959 by Charles Ford and colleagues in Harwell near Oxford, and Guy's Hospital in London. It was found in a 14-year-old girl with signs of Turner syndrome.


title: Raytheon Technologies

text: Raytheon Technologies Corporation is an American multinational aerospace and defense conglomerate headquartered in Arlington, Virginia. It is one of the largest aerospace and defense manufacturers in the world by revenue and market capitalization. In addition, it is one of the largest providers of intelligence services. Raytheon Technologies manufactures aircraft engines, avionics, aerostructures, cybersecurity, guided missiles, air defense systems, satellites, and drones. The company is also a large military contractor, getting a significant portion of its revenue from the U.S. government.


title: Raytheon Technologies

text: The company is the result of the merger of equals between the aerospace subsidiaries of United Technologies Corporation (UTC) and the Raytheon Company, which was completed on April 3, 2020. Before the merger, UTC spun off its non-aerospace subsidiaries Otis Elevator Company and Carrier Corporation. UTC is the nominal survivor of the merger but it changed its name to Raytheon Technologies and relocated its headquarters to Waltham, Massachusetts. Former UTC CEO and chairman Gregory J. Hayes is Chairman and CEO of the combined company.


title: Raytheon Technologies

text: The company has four subsidiaries: Collins Aerospace, Pratt & Whitney, Raytheon Intelligence & Space and Raytheon Missiles & Defense.


title: Raytheon Technologies

text: On June 7, 2022, the company announced plans to move its global headquarters to Arlington, Virginia. The move was completed in July.


title: Raytheon Technologies

text: The Raytheon Company was founded in 1922 in Cambridge, Massachusetts, by Laurence K. Marshall, Vannevar Bush, and Charles G. Smith as the American Appliance Company. Its focus, which was originally on new refrigeration technology, soon shifted to electronics. The company's first product was a gaseous (helium) rectifier that was based on Charles Smith's earlier astronomical research of the star Zeta Puppis. The electron tube was christened with the name "Raytheon" ("light of/from the gods") and was used in a battery eliminator, a type of radio-receiver power supply that plugged into the power grid in place of large batteries. This made it possible to convert household alternating current to direct current for radios and thus eliminate the need for expensive, short-lived batteries.


title: Raytheon Technologies

text: In 1925, the company changed its name to Raytheon Manufacturing Company and began marketing its rectifier, under the Raytheon brand name, with commercial success. In 1928, Raytheon merged with Q.R.S. Company, an American manufacturer of electron tubes and switches, to form the successor of the same name, Raytheon Manufacturing Company. By the 1930s, it had already grown to become one of the world's largest vacuum tube manufacturing companies. In 1933 it diversified by acquiring Acme-Delta Company, a producer of transformers, power equipment, and electronic auto parts.


title: Raytheon Technologies

text: During World War II, Raytheon mass manufactured magnetron tubes for use in microwave radar sets and then complete radar systems. At war's end in 1945, the company was responsible for about 80 percent of all magnetrons manufactured. During the war, Raytheon also pioneered the production of shipboard radar systems, particularly for submarine detection. Raytheon ranked 71st among United States corporations in the value of World War II military production contracts. In 1945, Raytheon's Percy Spencer invented the microwave oven by discovering that the magnetron could rapidly heat food. In 1947, the company demonstrated the Radarange microwave oven for commercial use.


title: Raytheon Technologies

text: After the war, Raytheon developed the first guidance system for a missile that could intercept a flying target. In 1948, Raytheon began to manufacture guided missiles, including the SAM-N-2 Lark, the air-to-air AIM-7 Sparrow, and the ground-to-air MIM-23 Hawk missiles. In 1959, Raytheon acquired the marine electronics company Apelco Applied Electronics, which significantly increased its strength in commercial marine navigation and radio gear, and changed its name to Raytheon Company.


title: Raytheon Technologies

text: During the post-war years, Raytheon also made generally low- to medium-powered radio and television transmitters and related equipment for the commercial market. In the 1950s, Raytheon began manufacturing transistors, including the CK722, priced for and marketed to hobbyists. Under the direction of Thomas L. Phillips in 1965, it acquired Amana Refrigeration, Inc., a manufacturer of refrigerators and air conditioners. Using the Amana brand name and its distribution channels, Raytheon began selling the first countertop household microwave oven in 1967 and became a dominant manufacturer in the microwave oven business.


title: Raytheon Technologies

text: In 1991, during the Persian Gulf War, Raytheon's Patriot missile received great international exposure, resulting in a substantial increase in sales for the company outside the United States. In an effort to establish leadership in the defense electronics business, Raytheon purchased in quick succession Dallas-based E-Systems (1995); Chrysler Corporation's defense electronics and aircraft-modification businesses, and the defense unit of Texas Instruments, Defense Systems & Electronics Group (1997). Also in 1997, Raytheon acquired the aerospace and defense business of Hughes Aircraft Company from Hughes Electronics Corporation, a subsidiary of General Motors, which included a number of product lines previously purchased by Hughes Electronics, including the former General Dynamics missile business (Pomona facility), the defense portion of Delco Electronics (Delco Systems Operations), and Magnavox Electronic Systems. Raytheon also divested itself of several nondefense businesses in the 1990s, including Amana Refrigeration and Seismograph Service Ltd (sold to Schlumberger-Geco-Prakla).


title: Raytheon Technologies

text: In November 2007, Raytheon purchased robotics company Sarcos, and in October 2009, Raytheon acquired BBN Technologies. In December 2010, Applied Signal Technology agreed to be acquired by Raytheon for $490 million.


title: Raytheon Technologies

text: In October 2014, Raytheon beat rivals Lockheed Martin and Northrop Grumman for a contract to build 3DELRR, a next-generation long-range radar system, for the US Air Force worth an estimated $1 billion. The contract award was immediately protested by Raytheon's competitors. After re-evaluating the bids following the protests, the US Air Force decided to delay awarding the 3DELRR EMD contract until 2017 and was to issue an amended solicitation at the end of July 2016. In 2017 the Air Force again awarded the contract to Raytheon.


title: Raytheon Technologies

text: In May 2015, Raytheon acquired cybersecurity firm Websense, Inc. from Vista Equity Partners for $1.9 billion and combined it with RCP, formerly part of its IIS segment to form Raytheon|Websense. In October 2015, Raytheon|Websense acquired Foreground Security, a provider of security operations centers, managed security service solutions and cybersecurity professional services, for $62 million. In January 2016, Raytheon|Websense acquired the firewall provider Stonesoft from Intel Security for an undisclosed amount and renamed itself to Forcepoint.


title: Raytheon Technologies

text: In July 2016, Poland's Defence Minister Antoni Macierewicz planned to sign a letter of intent with Raytheon for a $5.6 billion deal to upgrade its Patriot missile-defence shield, and in 2017, Saudi Arabia signed business deals worth billions of dollars with multiple American companies, including Raytheon.


title: Raytheon Technologies

text: In February 2020, Raytheon completed the first radar antenna array for the US Army's new missile defense radar, known as the Lower Tier Air and Missile Defense Sensor (LTAMDS), to replace the service's Patriot air and missile defense system sensor.


title: Raytheon Technologies

text: In 1929, William Boeing's Boeing Airplane & Transport Corporation teamed up with Frederick Rentschler's Pratt & Whitney to form the United Aircraft and Transport Corporation, a large, vertically-integrated, amalgamated firm, uniting business interests in all aspects of aviation—a combination of aircraft engine and airframe manufacturing and airline business, to serve all aviation markets, both civil aviation (cargo, passenger, private, air mail) and military aviation. After the Air Mail scandal of 1934, the U.S. government concluded that such large holding companies as United Aircraft and Transport were anti-competitive, and new antitrust laws were passed forbidding airframe or engine manufacturers from having interests in airlines.


title: Raytheon Technologies

text: United Aircraft Corporation was formed in 1934 from the portions of United Aircraft and Transport east of the Mississippi River (Pratt & Whitney, Sikorsky, Vought, and Hamilton Standard Propeller Company), headquartered in Hartford with Frederick Rentschler, founder of Pratt & Whitney, as president.


title: Raytheon Technologies

text: United Aircraft became a component of the Dow Jones Industrial Average on March 4, 1939, when United Aircraft and AT&T were added to replace Nash Motors and International Business Machines. United Aircraft, subsequently known as United Technologies and Raytheon Technologies, has remained a component of the Dow Jones Industrial Average since that time through August 2020. It was announced that starting August 31, 2020, Raytheon Technologies would be substituted in the Dow Jones Industrial Average by Honeywell International.


title: Raytheon Technologies

text: During World War II, United Aircraft ranked sixth among United States corporations in the value of wartime production contracts. At the close of the war, United Aircraft entered the emerging markets for jet engines and helicopters, via Pratt & Whitney and Sikorsky, respectively.


title: Raytheon Technologies

text: In the 1950s, United Aircraft began developing jet engines, including the Pratt & Whitney J57, the most powerful jet engine on the market for some years. In the 1960s, Pratt & Whitney produced the Pratt & Whitney JT9D for the Boeing 747.


title: Raytheon Technologies

text: In 1974, Harry Gray left Litton Industries to become the CEO of United Aircraft. He pursued a strategy of growth and diversification, changing the parent corporation's name to United Technologies Corporation (UTC) in 1975 to reflect the intent to diversify into numerous high tech fields beyond aerospace. (The change became official on May 1, 1975.) The diversification was partially to balance civilian business against any overreliance on military business. UTC became a mergers and acquisitions (M&A)–focused organization, with various forced takeovers of unwilling smaller corporations. The next year (1976), UTC forcibly acquired Otis Elevator. In 1979, Carrier Refrigeration was acquired;


title: Raytheon Technologies

text: At one point the military portion of UTC's business, whose sensitivity to "excess profits" and boom/bust demand drove UTC to diversify away from it, actually carried the weight of losses incurred by the commercial M&A side of the business. Although M&A activity was not new to United Aircraft, the M&A activity of the 1970s and 1980s was higher-stakes and arguably unfocused. Rather than aviation being the central theme of UTC businesses, high tech (of any type) was the new theme. Some Wall Street watchers questioned the true value of M&A at almost any price, seemingly for its own sake.


title: Raytheon Technologies

text: In 1999, UTC acquired Sundstrand Corporation and merged it into UTC's Hamilton Standard unit to form Hamilton Sundstrand. In 2003, UTC entered the fire and security business by purchasing Chubb Security. In 2004, UTC acquired the Schweizer Aircraft Corporation which planned to operate as a wholly owned subsidiary under their Sikorsky Aircraft division. In 2005, UTC further pursued its stake in the fire and security business by purchasing Kidde. Also in 2005, UTC acquired Boeing's Rocketdyne division, which was merged into the Pratt & Whitney business unit and renamed Pratt & Whitney Rocketdyne (later sold to Aerojet and merged into Aerojet Rocketdyne). In November 2008, UTC's Carrier Corporation acquired NORESCO, an energy service company.


title: Raytheon Technologies

text: In 2010, UTC conducted its largest acquisition to date, General Electric's security equipment business for US$1.8 billion, a move to support UTC's Fire & Security unit.


title: Raytheon Technologies

text: In September 2011, UTC acquired a $18.4 billion deal (including $1.9 billion in net debt assumed) for aircraft components maker Goodrich Corporation. In July 2012, United Technologies acquired Goodrich and merged it with Hamilton Sundstrand, forming UTC Aerospace Systems.


title: Raytheon Technologies

text: In November 2018, UTC acquired Rockwell Collins for $23 billion ($30 billion including Rockwell Collins' net debt). As part of the deal, Pratt and Whitney and the newly-formed Collins Aerospace remained under United Technologies, while Otis Elevator and UTC Climate, Controls & Security (doing business as Carrier) were spun off as two independent companies. The spin off was completed in March 2020.


title: Raytheon Technologies

text: In June 2019, United Technologies announced the intention to merge with the Raytheon Company. The combined company, valued at more than $100 billion after planned spinoffs, would be the world's second-largest aerospace-and-defense company by sales behind Boeing. Although UTC will be the nominal survivor, the merged company took the name Raytheon Technologies and based its headquarters at Raytheon's former campus in Waltham, Massachusetts, rather than UTC's former base in Farmington, Connecticut. The merger was completed in April 2020, forming Raytheon Technologies. Raytheon Technologies began trading at $51 per share, on the New York Stock Exchange under the ticker RTX.


title: Raytheon Technologies

text: On July 28, 2020 the company announced cutting of over 8,000 jobs in its commercial aviation division due to travel slowdown induced by the global COVID-19 pandemic.


title: Student's t-test

text: A "t"-test is any statistical hypothesis test in which the test statistic follows a Student's "t"-distribution under the null hypothesis. It is most commonly applied when the test statistic would follow a normal distribution if the value of a scaling term in the test statistic were known (typically, the scaling term is unknown and therefore a nuisance parameter). When the scaling term is estimated based on the data, the test statistic—under certain conditions—follows a Student's "t" distribution. The "t"-test's most common application is to test whether the means of two populations are different.


title: Student's t-test

text: The term ""t"-statistic" is abbreviated from "hypothesis test statistic". In statistics, the t-distribution was first derived as a posterior distribution in 1876 by Helmert and Lüroth. The t-distribution also appeared in a more general form as Pearson Type IV distribution in Karl Pearson's 1895 paper. However, the T-Distribution, also known as Student's t-distribution, gets its name from William Sealy Gosset who first published it in English in 1908 in the scientific journal Biometrika using the pseudonym "Student" because his employer preferred staff to use pen names when publishing scientific papers. Gosset worked at the Guinness Brewery in Dublin, Ireland, and was interested in the problems of small samples – for example, the chemical properties of barley with small sample sizes. Hence a second version of the etymology of the term Student is that Guinness did not want their competitors to know that they were using the t-test to determine the quality of raw material (see Student's "t"-distribution for a detailed history of this pseudonym, which is not to be confused with the literal term "student"). Although it was William Gosset after whom the term "Student" is penned, it was actually through the work of Ronald Fisher that the distribution became well known as "Student's distribution" and "Student's t-test".


title: Student's t-test

text: Gosset had been hired owing to Claude Guinness's policy of recruiting the best graduates from Oxford and Cambridge to apply biochemistry and statistics to Guinness's industrial processes. Gosset devised the "t"-test as an economical way to monitor the quality of stout. The "t"-test work was submitted to and accepted in the journal "Biometrika" and published in 1908.


title: Student's t-test

text: Guinness had a policy of allowing technical staff leave for study (so-called "study leave"), which Gosset used during the first two terms of the 1906–1907 academic year in Professor Karl Pearson's Biometric Laboratory at University College London. Gosset's identity was then known to fellow statisticians and to editor-in-chief Karl Pearson.


title: Student's t-test

text: where is the sample mean from a sample , of size , is the standard error of the mean, formula_2 is the estimate of the standard deviation of the population, and is the population mean.


title: Student's t-test

text: In the "t"-test comparing the means of two independent samples, the following assumptions should be met:


title: Student's t-test

text: For exactness, the "t"-test and "Z"-test require normality of the sample means, and the "t"-test additionally requires that the sample variance follows a scaled "χ" distribution, and that the sample mean and sample variance be statistically independent. Normality of the individual data values is not required if these conditions are met. By the central limit theorem, sample means of moderately large samples are often well-approximated by a normal distribution even if the data are not normally distributed. For non-normal data, the distribution of the sample variance may deviate substantially from a "χ" distribution.


title: Student's t-test

text: However, if the sample size is large, Slutsky's theorem implies that the distribution of the sample variance has little effect on the distribution of the test statistic. That is as sample size formula_3 increases:


title: Student's t-test

text: Two-sample "t"-tests for a difference in means involve independent samples (unpaired samples) or paired samples. Paired "t"-tests are a form of blocking, and have greater power (probability of avoiding a type II error, also known as a false negative) than unpaired tests when the paired units are similar with respect to "noise factors" that are independent of membership in the two groups being compared. In a different context, paired "t"-tests can be used to reduce the effects of confounding factors in an observational study.


title: Student's t-test

text: The independent samples "t"-test is used when two separate sets of independent and identically distributed samples are obtained, and one variable from each of the two populations is compared. For example, suppose we are evaluating the effect of a medical treatment, and we enroll 100 subjects into our study, then randomly assign 50 subjects to the treatment group and 50 subjects to the control group. In this case, we have two independent samples and would use the unpaired form of the "t"-test.


title: Student's t-test

text: Paired samples "t"-tests typically consist of a sample of matched pairs of similar units, or one group of units that has been tested twice (a "repeated measures" "t"-test).


title: Student's t-test

text: A typical example of the repeated measures "t"-test would be where subjects are tested prior to a treatment, say for high blood pressure, and the same subjects are tested again after treatment with a blood-pressure-lowering medication. By comparing the same patient's numbers before and after treatment, we are effectively using each patient as their own control. That way the correct rejection of the null hypothesis (here: of no difference made by the treatment) can become much more likely, with statistical power increasing simply because the random interpatient variation has now been eliminated. However, an increase of statistical power comes at a price: more tests are required, each subject having to be tested twice. Because half of the sample now depends on the other half, the paired version of Student's "t"-test has only degrees of freedom (with being the total number of observations). Pairs become individual test units, and the sample has to be doubled to achieve the same number of degrees of freedom. Normally, there are degrees of freedom (with being the total number of observations).


title: Student's t-test

text: A paired samples "t"-test based on a "matched-pairs sample" results from an unpaired sample that is subsequently used to form a paired sample, by using additional variables that were measured along with the variable of interest. The matching is carried out by identifying pairs of values consisting of one observation from each of the two samples, where the pair is similar in terms of other measured variables. This approach is sometimes used in observational studies to reduce or eliminate the effects of confounding factors.


title: Student's t-test

text: Explicit expressions that can be used to carry out various "t"-tests are given below. In each case, the formula for a test statistic that either exactly follows or closely approximates a "t"-distribution under the null hypothesis is given. Also, the appropriate degrees of freedom are given in each case. Each of these statistics can be used to carry out either a one-tailed or two-tailed test.


title: Student's t-test

text: Once the "t" value and degrees of freedom are determined, a "p"-value can be found using a table of values from Student's "t"-distribution. If the calculated "p"-value is below the threshold chosen for statistical significance (usually the 0.10, the 0.05, or 0.01 level), then the null hypothesis is rejected in favor of the alternative hypothesis.


title: Student's t-test

text: In testing the null hypothesis that the population mean is equal to a specified value , one uses the statistic


title: Student's t-test

text: where formula_8 is the sample mean, is the sample standard deviation and is the sample size. The degrees of freedom used in this test are .


title: Student's t-test

text: Although the parent population does not need to be normally distributed, the distribution of the population of sample means formula_8 is assumed to be normal.


title: Student's t-test

text: By the central limit theorem, if the observations are independent and the second moment exists, then formula_10 will be approximately normal N(0;1).


title: Student's t-test

text: where is known, and are unknown, is a normally distributed random variable with mean 0 and unknown variance , and is the outcome of interest. We want to test the null hypothesis that the slope is equal to some specified value (often taken to be 0, in which case the null hypothesis is that and are uncorrelated).


title: Student's t-test

text: has a "t"-distribution with degrees of freedom if the null hypothesis is true. The standard error of the slope coefficient:


title: Student's t-test

text: Here is the pooled standard deviation for and and are the unbiased estimators of the population variance. The denominator of is the standard error of the difference between two means.


title: Student's t-test

text: This test is used only when it can be assumed that the two distributions have the same variance. (When this assumption is violated, see below.)


title: Student's t-test

text: The previous formulae are a special case of the formulae below, one recovers them when both samples are equal in size: .


title: Student's t-test

text: is the pooled standard deviation of the two samples: it is defined in this way so that its square is an unbiased estimator of the common variance whether or not the population means are the same. In these formulae, is the number of degrees of freedom for each group, and the total sample size minus two (that is, ) is the total number of degrees of freedom, which is used in significance testing.


title: Student's t-test

text: This test, also known as Welch's "t"-test, is used only when the two population variances are not assumed to be equal (the two sample sizes may or may not be equal) and hence must be estimated separately. The statistic to test whether the population means are different is calculated as:


title: Student's t-test

text: Here is the unbiased estimator of the variance of each of the two samples with = number of participants in group ( = 1 or 2). In this case


title: Student's t-test

text: is not a pooled variance. For use in significance testing, the distribution of the test statistic is approximated as an ordinary Student's "t"-distribution with the degrees of freedom calculated using


title: Student's t-test

text: This is known as the Welch–Satterthwaite equation. The true distribution of the test statistic actually depends (slightly) on the two unknown population variances (see Behrens–Fisher problem).


title: Student's t-test

text: The test deals with the famous Behrens–Fisher problem, i.e., comparing the difference between the means of two normally distributed populations when the variances of the two populations are not assumed to be equal, based on two independent samples.


title: Student's t-test

text: The test is developed as an exact test that allows for unequal sample sizes and unequal variances of two populations. The exact property still holds even with small extremely small and unbalanced sample sizes (e.g. formula_27).


title: Student's t-test

text: Let formula_28 and formula_29 be the i.i.d. sample vectors (formula_30) from formula_31 and formula_32 separately.


title: Student's t-test

text: Let formula_33 be an formula_34 orthogonal matrix whose elements of the first row are all formula_35, similarly, let formula_36 be the first n rows of an formula_37 orthogonal matrix (whose elements of the first row are all formula_38).


title: Student's t-test

text: This test is used when the samples are dependent; that is, when there is only one sample that has been tested twice (repeated measures) or when there are two samples that have been matched or "paired". This is an example of a paired difference test. The "t" statistic is calculated as


title: Student's t-test

text: where formula_46 and formula_47 are the average and standard deviation of the differences between all pairs. The pairs are e.g. either one person's pre-test and post-test scores or between-pairs of persons matched into meaningful groups (for instance drawn from the same family or age group: see table). The constant is zero if we want to test whether the average of the difference is significantly different. The degree of freedom used is , where represents the number of pairs.


title: Student's t-test

text: We will carry out tests of the null hypothesis that the means of the populations from which the two samples were taken are equal.


title: Student's t-test

text: The difference between the two sample means, each denoted by , which appears in the numerator for all the two-sample testing approaches discussed above, is


title: Student's t-test

text: The sample standard deviations for the two samples are approximately 0.05 and 0.11, respectively. For such small samples, a test of equality between the two population variances would not be very powerful. Since the sample sizes are equal, the two forms of the two-sample "t"-test will perform similarly in this example.


title: Student's t-test

text: The "t"-test provides an exact test for the equality of the means of two i.i.d. normal populations with unknown, but equal, variances. (Welch's "t"-test is a nearly exact test for the case where the data are normal but the variances may differ.) For moderately large samples and a one tailed test, the "t"-test is relatively robust to moderate violations of the normality assumption. In large enough samples, the t-test asymptotically approaches the "z"-test, and becomes robust even to large deviations from normality.


title: Student's t-test

text: If the data are substantially non-normal and the sample size is small, the "t"-test can give misleading results. See Location test for Gaussian scale mixture distributions for some theory related to one particular family of non-normal distributions.


title: Student's t-test

text: When the normality assumption does not hold, a non-parametric alternative to the "t"-test may have better statistical power. However, when data are non-normal with differing variances between groups, a t-test may have better type-1 error control than some non-parametric alternatives. Furthermore, non-parametric methods, such as the Mann-Whitney U test discussed below, typically do not test for a difference of means, so should be used carefully if a difference of means is of primary scientific interest. For example, Mann-Whitney U test will keep the type 1 error at the desired level alpha if both groups have the same distribution. It will also have power in detecting an alternative by which group B has the same distribution as A but after some shift by a constant (in which case there would indeed be a difference in the means of the two groups). However, there could be cases where group A and B will have different distributions but with the same means (such as two distributions, one with positive skewness and the other with a negative one, but shifted so to have the same means). In such cases, MW could have more than alpha level power in rejecting the Null hypothesis but attributing the interpretation of difference in means to such a result would be incorrect.


title: Student's t-test

text: In the presence of an outlier, the t-test is not robust. For example, for two independent samples when the data distributions are asymmetric (that is, the distributions are skewed) or the distributions have large tails, then the Wilcoxon rank-sum test (also known as the Mann–Whitney "U" test) can have three to four times higher power than the "t"-test. The nonparametric counterpart to the paired samples "t"-test is the Wilcoxon signed-rank test for paired samples. For a discussion on choosing between the "t"-test and nonparametric alternatives, see Lumley, et al. (2002).


title: Student's t-test

text: One-way analysis of variance (ANOVA) generalizes the two-sample "t"-test when the data belong to more than two groups.


title: Student's t-test

text: When both paired observations and independent observations are present in the two sample design, assuming data are missing completely at random (MCAR), the paired observations or independent observations may be discarded in order to proceed with the standard tests above. Alternatively making use of all of the available data, assuming normality and MCAR, the generalized partially overlapping samples t-test could be used.


title: Student's t-test

text: A generalization of Student's "t" statistic, called Hotelling's "t"-squared statistic, allows for the testing of hypotheses on multiple (often correlated) measures within the same sample. For instance, a researcher might submit a number of subjects to a personality test consisting of multiple personality scales (e.g. the Minnesota Multiphasic Personality Inventory). Because measures of this type are usually positively correlated, it is not advisable to conduct separate univariate "t"-tests to test hypotheses, as these would neglect the covariance among measures and inflate the chance of falsely rejecting at least one hypothesis (Type I error). In this case a single multivariate test is preferable for hypothesis testing. Fisher's Method for combining multiple tests with "alpha" reduced for positive correlation among tests is one. Another is Hotelling's "T" statistic follows a "T" distribution. However, in practice the distribution is rarely used, since tabulated values for "T" are hard to find. Usually, "T" is converted instead to an "F" statistic.


title: Student's t-test

text: For a one-sample multivariate test, the hypothesis is that the mean vector () is equal to a given vector (). The test statistic is Hotelling's "t":


title: Student's t-test

text: For a two-sample multivariate test, the hypothesis is that the mean vectors () of two samples are equal. The test statistic is Hotelling's two-sample "t":


title: Student's t-test

text: Many spreadsheet programs and statistics packages, such as QtiPlot, LibreOffice Calc, Microsoft Excel, SAS, SPSS, Stata, DAP, gretl, R, Python, PSPP, MATLAB and Minitab, include implementations of Student's "t"-test.


title: Schadenfreude

text: Schadenfreude (; ; 'harm-joy') is the experience of pleasure, joy, or self-satisfaction that comes from learning of or witnessing the troubles, failures, or humiliation of another. It is a borrowed word from German, with no direct translation, that originated in the 18th century.


title: Schadenfreude

text: Schadenfreude has been detected in children as young as 24 months and may be an important social emotion establishing "inequity aversion".


title: Schadenfreude

text: Schadenfreude is a term borrowed from German. It is a compound of ("damage/harm") and ("joy"). The German word was first mentioned in English texts in 1852 and 1867, and first used in English running text in 1895. In German, it was first attested in the 1740s.


title: Schadenfreude

text: The earliest seems to be Christoph Starke, Synopsis bibliothecae exegeticae in Vetus Testamentum. Leipzig 1750.


title: Schadenfreude

text: Although common nouns normally are not capitalised in English, schadenfreude sometimes is capitalised following the German convention.


title: Schadenfreude

text: Researchers have found that there are three driving forces behind schadenfreude – aggression, rivalry, and justice.


title: Schadenfreude

text: Self-esteem has a negative relationship with the frequency and intensity of schadenfreude experienced by an individual; individuals with less self-esteem tend to experience schadenfreude more frequently and intensely.


title: Schadenfreude

text: It is hypothesized that this inverse relationship is mediated through the human psychological inclination to define and protect their self- and in-group- identity or self-conception. Specifically, for someone with high self-esteem, seeing another person fail may still bring them a small (but effectively negligible) surge of confidence because the observer's high self-esteem significantly lowers the threat they believe the visibly-failing human poses to their status or identity. Since this confident individual perceives that, regardless of circumstances, the successes and failures of the other person will have little impact on their own status or well-being, they have very little emotional investment in how the other person fares, be it positive or negative.


title: Schadenfreude

text: Conversely, for someone with low self-esteem, someone who is more successful poses a threat to their sense of self, and seeing this person fall can be a source of comfort because they perceive a relative improvement in their internal or in-group standing.


title: Schadenfreude

text: "Schadenfreude" has equivalents in many other languages (such as: in Dutch and Swedish ), but no commonly-used precise English single-word equivalent. There are other ways to express the concept in English.


title: Schadenfreude

text: "Epicaricacy" is a seldom-used direct equivalent, borrowed from Greek "epichairekakia" (ἐπιχαιρεκακία, first attested in Aristotle) from ἐπί "epi" 'upon', χαρά "chara" 'joy', and κακόν "kakon" 'evil'.


title: Schadenfreude

text: Tall poppy syndrome is a cultural phenomenon where people of high status are resented, attacked, cut down, or criticized because they have been classified as better than their peers. This is similar to "begrudgery", the resentment or envy of the success of a peer. If someone were to feel joy by the victim's fall from grace, they would be experiencing schadenfreude.


title: Schadenfreude

text: "Roman holiday" is a metaphor from Byron's poem "Childe Harold's Pilgrimage", where a gladiator in ancient Rome expects to be "butchered to make a Roman holiday" while the audience would take pleasure from watching his suffering. The term suggests debauchery and disorder in addition to sadistic enjoyment.


title: Schadenfreude

text: Morose delectation (), meaning "the habit of dwelling with enjoyment on evil thoughts", was considered by the medieval church to be a sin. French writer Pierre Klossowski maintained that the appeal of sadism is morose delectation.


title: Schadenfreude

text: "Gloating" is an English word of similar meaning, where "gloat" means "to observe or think about something with triumphant and often malicious satisfaction, gratification, or delight" (e.g., to gloat over an enemy's misfortune). Gloating is different from schadenfreude in that it does not necessarily require malice (one may gloat to a friend without ill intent about having defeated him in a game), and that it describes an action rather than a state of mind (one typically gloats to the subject of the misfortune or to a third party). Also, unlike schadenfreude, where the focus is on another's misfortune, gloating often brings to mind inappropriately celebrating or bragging about one's own good fortune without any particular focus on the misfortune of others.


title: Schadenfreude

text: Permutations of the concept of pleasure at another's unhappiness are: pleasure at another's happiness, displeasure at another's happiness, and displeasure at another's unhappiness. Words for these concepts are sometimes cited as antonyms to schadenfreude, as each is the opposite in some way.


title: Schadenfreude

text: There is no common English term for pleasure at another's happiness. The pseudo-German coinage "freudenfreude" is occasionally used in English. Writers on Buddhism speak of "mudita" and polyamorists speak of "compersion". The Hebrew slang term "firgun" refers to happiness at another's accomplishment.


title: Schadenfreude

text: Displeasure at another's happiness is involved in envy, and perhaps in jealousy. The coinage "freudenschade" similarly means sorrow at another's success.


title: Schadenfreude

text: Displeasure at another's good fortune is "Gluckschmerz", a pseudo-German word coined in 1985 as a joke by the pseudonymous Wanda Tinasky; the correct German form would be "Glücksschmerz". It has since been used in academic contexts.


title: Schadenfreude

text: Sadism gives pleasure through the "infliction" of pain, whereas schadenfreude is pleasure on "observing" misfortune and in particular, the fact that the other somehow deserved the misfortune.


title: Schadenfreude

text: The word "schadenfreude" had been blended with other words to form neologisms as early as 1993, when Lincoln Caplan, in his book "Skadden: Power, Money, and the Rise of a Legal Empire", used the word "Skaddenfreude" to describe the delight that competitors of Skadden Arps took in its troubles of the early 1990s. Others include "spitzenfreude", coined by "The Economist" to refer to the fall of Eliot Spitzer and "Schadenford", coined by "Toronto Life" in regard to Canadian politician Rob Ford.


title: Schadenfreude

text: The Book of Proverbs mentions an emotion similar to schadenfreude: "Rejoice not when thine enemy falleth, and let not thine heart be glad when he stumbleth: Lest the LORD see it, and it displease him, and he turn away his wrath from him." (Proverbs 24:17–18, King James Version).


title: Schadenfreude

text: In East Asia, the emotion of feeling joy from seeing the hardship of others was described as early as late 4th century BCE. The phrase () first appeared separately as (), meaning the feeling of joy from seeing the hardship of others, and (), meaning the happiness derived from the unfortunate situation of others, in the ancient Chinese text (). The phrase () is still used among Chinese speakers.


title: Schadenfreude

text: In the "Nicomachean Ethics", Aristotle used "epikhairekakia" (ἐπιχαιρεκακία in Greek) as part of a triad of terms, in which "epikhairekakia" stands as the opposite of "phthonos" (φθόνος), and "nemesis" (νέμεσις) occupies the mean. "Nemesis" is "a painful response to another's undeserved good fortune", while "phthonos" is a painful response to any good fortune of another, deserved or not. The "epikhairekakos" (ἐπιχαιρέκακος) person takes pleasure in another's ill fortune.


title: Schadenfreude

text: Lucretius characterises the emotion in an extended simile in "De rerum natura": "Suave, mari magno turbantibus aequora ventis, e terra magnum alterius spectare laborem", "It is pleasant to watch from the land the great struggle of someone else in a sea rendered great by turbulent winds." The abbreviated Latin tag "suave mare magno" recalled the passage to generations familiar with the Latin classics.


title: Schadenfreude

text: Caesarius of Heisterbach regards "delight in the adversity of a neighbour" as one of the "daughters of envy... which follows anger" in his "Dialogue on Miracles".


title: Schadenfreude

text: The philosopher Arthur Schopenhauer mentioned schadenfreude as the most evil sin of human feeling, famously saying "To feel envy is human, to savor schadenfreude is diabolic."


title: Schadenfreude

text: The song "Schadenfreude" in the musical "Avenue Q", is a comedic exploration of the general public's relationship with the emotion.


title: Schadenfreude

text: Rabbi Harold S. Kushner in his book "When Bad Things Happen to Good People" describes schadenfreude as a universal, even wholesome reaction that cannot be helped. "There is a German psychological term, "Schadenfreude", which refers to the embarrassing reaction of relief we feel when something bad happens to someone else instead of to us." He gives examples and writes, "[People] don't wish their friends ill, but they can’t help feeling an embarrassing spasm of gratitude that [the bad thing] happened to someone else and not to them."


title: Schadenfreude

text: Susan Sontag's book "Regarding the Pain of Others", published in 2003, is a study of the issue of how the pain and misfortune of some people affects others, namely whether war photography and war paintings may be helpful as anti-war tools, or whether they only serve some sense of schadenfreude in some viewers.


title: Schadenfreude

text: Philosopher and sociologist Theodor Adorno defined schadenfreude as "... largely unanticipated delight in the suffering of another, which is cognized as trivial and/or appropriate."


title: Schadenfreude

text: A "New York Times" article in 2002 cited a number of scientific studies of schadenfreude, which it defined as "delighting in others' misfortune". Many such studies are based on social comparison theory, the idea that when people around us have bad luck, we look better to ourselves. Other researchers have found that people with low self-esteem are more likely to feel schadenfreude than are those who have high self-esteem.


title: Schadenfreude

text: A 2003 study examined intergroup schadenfreude within the context of sports, specifically an international football (soccer) competition. The study focused on the German and Dutch football teams and their fans. The results of this study indicated that the emotion of schadenfreude is very sensitive to circumstances that make it more or less legitimate to feel such malicious pleasure toward a sports rival.


title: Schadenfreude

text: A 2011 study by Cikara and colleagues using functional magnetic resonance imaging (fMRI) examined schadenfreude among Boston Red Sox and New York Yankees fans, and found that fans showed increased activation in brain areas correlated with self-reported pleasure (ventral striatum) when observing the rival team experience a negative outcome (e.g., a strikeout). By contrast, fans exhibited increased activation in the anterior cingulate and insula when viewing their own team experience a negative outcome.


title: Schadenfreude

text: A 2006 experiment about "justice served" suggests that men, but not women, enjoy seeing "bad people" suffer. The study was designed to measure empathy by watching which brain centers are stimulated when subjects observed via fMRI see someone experiencing physical pain. Researchers expected that the brain's empathy center of subjects would show more stimulation when those seen as "good" got an electric shock, than would occur if the shock was given to someone the subject had reason to consider "bad". This was indeed the case, but for male subjects, the brain's pleasure centers also lit up when someone got a shock that the male thought was "well-deserved".


title: Schadenfreude

text: Brain-scanning studies show that schadenfreude is correlated with envy in subjects. Strong feelings of envy activated physical pain nodes in the brain's dorsal anterior cingulate cortex; the brain's reward centers, such as the ventral striatum, were activated by news that other people who were envied had suffered misfortune. The magnitude of the brain's schadenfreude response could even be predicted from the strength of the previous envy response.


title: Schadenfreude

text: A study conducted in 2009 provides evidence for people's capacity to feel schadenfreude in response to negative events in politics. The study was designed to determine whether or not there was a possibility that events containing objective misfortunes might produce schadenfreude. It was reported in the study that the likelihood of experiencing feelings of schadenfreude depends upon whether an individual's own party or the opposing party is suffering harm. This study suggests that the domain of politics is prime territory for feelings of schadenfreude, especially for those who identify strongly with their political party.


title: Schadenfreude

text: In 2014, research in the form of an online survey analyzed the relationship between schadenfreude and 'Dark Triad' traits (i.e. narcissism, Machiavellianism, and psychopathy). The findings showed that those respondents who had higher levels of Dark Triad traits also had higher levels of schadenfreude, engaged in greater anti-social activities and had greater interests in sensationalism.


title: Auliʻi Cravalho

text: Chloe Auliʻi Cravalho (; born November 22, 2000) is an American actress and singer who made her acting debut as the voice of the titular character in the 2016 Disney 3D computer-animated musical feature film "Moana". She went on to star in the NBC drama series "Rise" (2018), the Netflix drama film "All Together Now" (2020) and the Hulu romantic comedy "Crush" (2022).


title: Auliʻi Cravalho

text: Cravalho was born in Kohala, Hawaii, to Cathleen Puanani Cravalho and Dwayne Cravalho. She is of Native Hawaiian, Puerto Rican, Portuguese, Chinese, and Irish descent. At the time she made her breakthrough, she was living in Mililani, Hawaii, with her mother and was in her freshman year of high school, singing soprano in the glee club at Kamehameha Schools' Kapālama campus.


title: Auliʻi Cravalho

text: Cravalho has stated that she was initially not going to audition for "Moana" because "there were already so many great submissions that I didn’t think I needed to try out.” However, an Oahu talent agent discovered her through a charity video contest and brought her to Los Angeles to audition for the role. Casting director Rachel Sutton has stated that Cravalho was the last person to audition out of hundreds of actresses.


title: Auliʻi Cravalho

text: In February 2017, it was announced that she had been cast in the pilot for the NBC drama "Rise", which was ordered to series on May 4, 2017. The series premiered on March 13, 2018, but NBC cancelled the series on May 15, 2018, due to low ratings.


title: Auliʻi Cravalho

text: In November 2017, Cravalho announced she was going to reprise her role as Moana in the first Hawaiian-language dubbed Disney film. The dubbed "Moana" premiered on June 10, 2018.


title: Auliʻi Cravalho

text: On November 5, 2019, Cravalho portrayed Ariel in ABC's "The Little Mermaid Live!," a live-action concert rendition of "The Little Mermaid". In 2020, she starred in "All Together Now", directed by Brett Haley for Netflix.


title: Auliʻi Cravalho

text: In 2020, Cravalho participated in "Acting for a Cause", a live classic play and screenplay reading series created, directed and produced by Brando Crawford. Cravalho played Gwendolen Fairfax in "The Importance of Being Earnest", Laertes in "Hamlet", Lady Catherine in "Pride and Prejudice", and Jeannie Bueller in "Ferris Bueller's Day Off". The reading raised funds for non-profit charities including Mount Sinai Medical Center.


title: Auliʻi Cravalho

text: Cravalho was cast as the title character, Hailey, in the animated comedy-adventure series "Hailey's On It!", which is slated to premiere in 2023.


title: Auliʻi Cravalho

text: In April 2020, Cravalho publicly came out as bisexual. In June 2021, Cravalho announced that she was accepted into Columbia University and subsequently revealed that she plans to major in environmental science at the school.


title: Justin.tv

text: Justin.tv was a website created by Justin Kan, Emmett Shear, Michael Seibel, and Kyle Vogt in 2007 to allow anyone to broadcast video online. Justin.tv user accounts were called "channels", like those on YouTube, and users were encouraged to broadcast a wide variety of user-generated live video content, called "broadcasts".


title: Justin.tv

text: The company was an Internet startup based in San Francisco, California, with seed funding from Paul Graham of seed capital firm Y Combinator and Series A funding with Alsop Louie Partners and Draper Associates.


title: Justin.tv

text: The original Justin.tv was a single channel featuring founder Justin Kan, who broadcast his life 24/7 and popularized the term lifecasting. In 2007, Justin Kan stopped broadcasting and Justin.tv relaunched into its later form as a network of thousands of channels.


title: Justin.tv

text: Users were permitted to broadcast to an unlimited number of people for free, and watching broadcasts did not require user registration. Broadcasts that were considered to contain potentially offensive content were available only to registered users over the age of 18. Broadcasts containing defamation, pornography or copyright violations, or encouraging criminal conduct, were prohibited by Justin.tv's terms of service.


title: Justin.tv

text: Justin.tv moved its gaming section to a new site called Twitch in June 2011, and Twitch and the parent company of Justin.tv rebranded as Twitch Interactive in February 2014. The Justin.tv services and brand were officially shut down in August 2014 so that the company could focus on Twitch, which was then acquired by Amazon later that month.


title: Justin.tv

text: The original Justin.tv was a single channel featuring Justin Kan. Wearing a webcam attached to a baseball cap and streamed online via a laptop-backpack system designed by co-founder Kyle Vogt, Kan decided he would wear the camera 24/7, and he began streaming continuous live video and audio at midnight March 19, 2007. Kan would be streaming his entire life (minus bathroom and bathing breaks) via a camera attached to his hat and a laptop rig created by Justin.tv co-founder, Kyle Vogt. While streaming, Kan interacted with viewers via an inbuilt chat system. Occasionally, viewers would attempt to troll Kan by falsely reporting him to the police ("swatting") or by sending large delivery orders to his apartment, two online harassment methods which remained popular long after the site's closure.


title: Justin.tv

text: The novelty of the concept attracted media attention, and Kan interviewed with Ann Curry on the "Today Show" (April 2, 2007), Tom Merritt on the first episode of "CNET Live", "Nightline" (April 6, 2007) and "World News Tonight" (April 8, 2007). His lifecasting project has been compared to "EDtv", "Being John Malkovich", and "The Truman Show."


title: Justin.tv

text: Some of the few original life casters still exist today, while many faded into obscurity. A few of the original and popular lifecasters include: iJustine, a caster who still makes YouTube videos and has over 7 million subscribers on YouTube; Mooncricket Films, a San Francisco life caster who began lifecasting since the launch of Justin.tv; and JoeInIraq, the first and only lifecaster to stream his lifecast in Iraq in 2007–2008 during the War in Iraq, giving the world a unique view of how troops spend their downtime while in a hostile environment.


title: Justin.tv

text: In the summer of 2007, Justin.tv became a platform for more than 60 different channels. The "Directory" at the top of each channel showed which channels were live and which were not broadcasting. Depending on the entry time, a visitor might have seen only a small selection of the available channels.


title: Justin.tv

text: By August 2007, channels were being added at an average rate of two a day, with content covering both lifecasters and event streaming. The international locations range from Australia, Brazil, the United Kingdom, and France to the Netherlands and Sweden. In some cases, a lifecaster might travel from one country to another, as was the case when Lisa Batey traveled from Brooklyn to Tokyo and Kyoto in 2007 and 2008. Not all the participants have mobile equipment, however, and most simply transmit an image of themselves sitting at their computer. During this same time frame, singer-songwriter Jody Marie Gnant and others began lifecasting on other websites such as Ustream, Stickam, Livestream, or began lifecasting independent of any major website.


title: Justin.tv

text: On October 2, 2007, Justin.tv became an open network, allowing members of the public to register and broadcast. By April 10, 2008, Kan stated in an Interview with Tom Merritt that Justin.tv had signed 30,000 broadcasting accounts.


title: Justin.tv

text: On March 14, 2008, Justin.tv added selectable "Categories" for broadcasters including: Featured, People & Lifecasting, Sports, Music & Radio, Gaming, News & Tech, Animals, Entertainment, Divas & Dudes.


title: Justin.tv

text: On Friday, June 27, 2008, Justin.tv added networks to the site, in which the user could make their own network with a forum, and officers that would act as moderators for the network. On Thursday, March 25, 2010, these networks were removed from the site.


title: Justin.tv

text: On Monday, October 27, 2008, Justin.tv added "Headlines" which allows users to make reports on other broadcasters doing interesting things on the site, which then becomes edited and published for all users on the website to read and comment.


title: Justin.tv

text: On Monday, April 5, 2010, Justin.tv changed the design of their archive page, renaming them to Past Broadcasts. Essentially all past broadcasts are saved as a clip, and deleted after 7 days. From the Past Broadcast you can highlight for permanent save.


title: Justin.tv

text: Justin.tv's broadcasting and viewing was based on Adobe Flash. Users could broadcast directly from the site, with Justin.tv using Flash to auto-detect and stream from an attached webcam. Justin.tv also supported broadcasting using other third-party software, most notably QuickTime Broadcaster, Camtwist, D3DGear Broadcaster, Flash Media Encoder, Wirecast, Open Broadcaster Software, FFSplit Broadcaster, XSplit Broadcaster and VLC, to allow broadcasters to add effects or stream higher quality video.


title: Justin.tv

text: Justin.tv had no default video quality setting; instead, it set bitrate on a case-by-case basis by testing the broadcaster's available bandwidth. The broadcaster could also manually adjust the bitrate before going live. While broadcasting from the browser, the maximum quality settings were 1,000kbps for video and 44 kHz for audio. In comparison, YouTube High Quality video at the time was 400–500kbps, and YouTube 720p high definition video is approximately 2,000kbps. The 1,000kbps limit could be exceeded by using alternate broadcasting methods, such as Flash Media Encoder and Quicktime Broadcaster, and 720p video in H.264 had been broadcast by some users.


title: Justin.tv

text: Following the Justin.tv re-design in July 2009, the default channel video size changed from a standard aspect ratio of pixels to a widescreen pixels.


title: Justin.tv

text: Like YouTube and other static video sites, Justin.tv allowed each channel to be accompanied with an HTML snippet, which allows users to embed video onto pages outside the Justin.tv site. Another snippet is given to embed the associated chatbox as well, thus allowing users to recreate the basic Justin.tv functionality on another page. Broadcasters have the option of disabling embedding for their specific channel.


title: Justin.tv

text: Following the release of the API in August 2009, Justin.tv released Flash SWF files that allows developers to include Justin.tv video in Flash projects.


title: Justin.tv

text: While the primary Justin.tv site was in English, there was support for users to translate the site into other languages. Two languages (Catalan and Spanish) had been translated completely, and an additional 17 were over 50% translated.


title: Justin.tv

text: Although Justin.tv attempted to align its policies with the Digital Millennium Copyright Act, it had been criticized for failing to ensure that its users respect copyright law. In August 2009, Justin.tv announced a deal with Fox to actively filter streams in real-time. Justin.tv used a filtering system from Vobile to detect and filter out any infringing content, and remove the channel from the website.


title: Justin.tv

text: During the period when Justin.tv consisted solely of Justin Kan lifecasting, Justin became the target of several pranks. A viewer spoofed Justin's caller ID (publicly available on the site) using an IP Relay service. On March 21, 2007, the spoofer called the San Francisco Police Department and filed a false report about a stabbing in the apartment. The following day, someone reported a fire at the apartment. The San Francisco emergency services then put Justin.tv's number on a list which requires a confirmation call before responding to any emergencies. Kan changed his number and kept the new one private.


title: Justin.tv

text: In July 2008, TheDefaced.org, a computer security group, released a non-malicious cross-site scripting (XSS) worm onto the Justin.tv site. After successfully propagating the worm, TheDefaced.org contacted Justin.tv programmers and worked with them to fix the vulnerability.


title: Justin.tv

text: In 2011, the American sports promotion company Zuffa sued Justin.tv for its users using the streaming service to watch pay-per-view matches of the UFC, violating certain trademark and copyright laws. In March 2012, Justin.tv won a partial dismissal of the lawsuit, with the lone exception being in regards to copyright violations. One month later in April, Justin.tv settled with Zuffa for an undisclosed amount and both sides requested the lawsuit be dismissed.


title: Justin.tv

text: On November 19, 2008, 19-year-old committed suicide while broadcasting to a room full of viewers on his Justin.tv channel by ingesting an overdose of opiates and benzodiazepines. He was also struggling with bipolar disorder. Biggs posted his suicide note online, as noted in "The New York Times".


title: Justin.tv

text: We regret that this has occurred and respect the privacy of the broadcaster and his family during this time. We have policies in place to discourage the distribution of distressing content and our community monitors the site accordingly. This content was flagged by our community, reviewed and removed according to our terms of service.


title: Vaudeville

text: Vaudeville (; ) is a theatrical genre of variety entertainment born in France at the end of the 19th century. A vaudeville was originally a comedy without psychological or moral intentions, based on a comical situation: a dramatic composition or light poetry, interspersed with songs or ballets. It became popular in the United States and Canada from the early 1880s until the early 1930s, but the idea of vaudeville's theatre changed radically from its French antecedent.


title: Vaudeville

text: In some ways analogous to music hall from Victorian Britain, a typical North American vaudeville performance was made up of a series of separate, unrelated acts grouped together on a common bill. Types of acts have included popular and classical musicians, singers, dancers, comedians, trained animals, magicians, ventriloquists, strongmen, female and male impersonators, acrobats, clowns, illustrated songs, jugglers, one-act plays or scenes from plays, athletes, lecturing celebrities, minstrels, and movies. A vaudeville performer is often referred to as a "vaudevillian".


title: Vaudeville

text: Vaudeville developed from many sources, also including the concert saloon, minstrelsy, freak shows, dime museums, and literary American burlesque. Called "the heart of American show business", vaudeville was one of the most popular types of entertainment in North America for several decades.


title: Vaudeville

text: The origin of the term is obscure but often explained as being derived from the French expression "voix de ville" ("voice of the city"). A second speculation is that it comes from the 15th-century songs on satire by poet Olivier Basselin, "Vau de Vire". In his "Connections" television series, science historian James Burke argues that the term is a corruption of the French "Vau de Vire" ("Vire River Valley", in English), an area known for its bawdy drinking songs and where Basselin lived. The "Oxford English Dictionary" also endorses the origin, a truncated form of ("song of the Valley of the Vire"). Around 1610, Jean le Houx collected these works as "", which is probably the direct origin of the word. Some, however, preferred the earlier term "variety" to what manager Tony Pastor called its "sissy and Frenchified" successor. Thus, vaudeville marketed itself as "variety" well into the 20th century.


title: Vaudeville

text: With its first subtle appearances within the early 1860s, vaudeville was not initially a common form of entertainment. The form gradually evolved from the concert saloon and variety hall into its mature form throughout the 1870s and 1880s. This more gentle form was known as "Polite Vaudeville".


title: Vaudeville

text: In the years before the American Civil War, entertainment existed on a different scale. Certainly, variety theatre existed before 1860 in Europe and elsewhere. In the US, as early as the first decades of the 19th century, theatergoers could enjoy a performance consisting of Shakespeare plays, acrobatics, singing, dancing, and comedy. As the years progressed, people seeking diversified amusement found an increasing number of ways to be entertained. Vaudeville was characterized by traveling companies touring through cities and towns. A handful of circuses regularly toured the country; dime museums appealed to the curious; amusement parks, riverboats, and town halls often featured "cleaner" presentations of variety entertainment; compared to saloons, music halls, and burlesque houses, which catered to those with a taste for the "risqué". In the 1840s, the minstrel show, another type of variety performance, and "the first emanation of a pervasive and purely American mass culture", grew to enormous popularity and formed what Nick Tosches called "the heart of 19th-century show business". A significant influence also came from "Dutch" (i.e., German or faux-German) minstrels and comedians. Medicine shows traveled the countryside offering programs of comedy, music, jugglers, and other novelties along with displays of tonics, salves, and miracle elixirs, while "Wild West" shows provided romantic vistas of the disappearing frontier, complete with trick riding, music and drama. Vaudeville incorporated these various itinerant amusements into a stable, institutionalized form centered in America's growing urban hubs.


title: Vaudeville

text: From the mid-1860s, impresario Tony Pastor, a former singing circus clown who had become a prominent variety theater performer and manager, capitalized on middle class sensibilities and spending power when he began to feature "polite" variety programs in his New York City theatres. Pastor opened his first "Opera House" on the Bowery in 1865, later moving his variety theater operation to Broadway and, finally, to Fourteenth Street near Union Square. He only began to use the term "vaudeville" in place of "variety" in early 1876. Hoping to draw a potential audience from female and family-based shopping traffic uptown, Pastor barred the sale of liquor in his theatres, eliminated bawdy material from his shows, and offered gifts of coal and hams to attendees. Pastor's experiment proved successful, and other managers soon followed suit.


title: Vaudeville

text: B. F. Keith took the next step, starting in Boston, where he built an empire of theatres and brought vaudeville to the US and Canada. Later, E. F. Albee, adoptive grandfather of the Pulitzer Prize-winning playwright Edward Albee, managed the chain to its greatest success. Circuits such as those managed by Keith-Albee provided vaudeville's greatest economic innovation and the principal source of its industrial strength. They enabled a chain of allied vaudeville houses that remedied the chaos of the single-theatre booking system by contracting acts for regional and national tours. These could easily be lengthened from a few weeks to two years.


title: Vaudeville

text: Albee also gave national prominence to vaudeville's trumpeting "polite" entertainment, a commitment to entertainment equally inoffensive to men, women and children. Acts that violated this ethos (e.g., those that used words such as "hell") were admonished and threatened with expulsion from the week's remaining performances or were canceled altogether. In spite of such threats, performers routinely flouted this censorship, often to the delight of the very audience members whose sensibilities were supposedly endangered. He eventually instituted a set of guidelines to be an audience member at his show, and these were reinforced by the ushers working in the theatre.


title: Vaudeville

text: This "polite entertainment" also extended to Keith's company members. He went to extreme measures to maintain this level of modesty. Keith even went as far as posting warnings backstage such as this: "Don't say 'slob' or 'son of a gun' or 'hully gee' on the stage unless you want to be canceled peremptorily... if you are guilty of uttering anything sacrilegious or even suggestive you will be immediately closed and will never again be allowed in a theatre where Mr. Keith is in authority." Along these same lines of discipline, Keith's theatre managers would occasionally send out blue envelopes with orders to omit certain suggestive lines of songs and possible substitutions for those words. If actors chose to ignore these orders or quit, they would get "a black mark" on their name and would never again be allowed to work on the Keith Circuit. Thus, actors learned to follow the instructions given to them by B. F. Keith for fear of losing their careers forever.


title: Vaudeville

text: By the late 1890s, vaudeville had large circuits, houses (small and large) in almost every sizable location, standardized booking, broad pools of skilled acts, and a loyal national following. One of the biggest circuits was Martin Beck's Orpheum Circuit. It incorporated in 1919 and brought together 45 vaudeville theatres in 36 cities throughout the US and Canada and a large interest in two vaudeville circuits. Another major circuit was that of Alexander Pantages. In his heyday, Pantages owned more than 30 vaudeville theatres and controlled, through management contracts, perhaps 60 more in both the US and Canada.