Regression can be used for prediction (including forecasting of time-series data), inference, hypothesis testing, and modeling of causal relationships. These uses of regression rely heavily on the underlying assumptions being satisfied. Regression analysis has been criticized as being misused for these purposes in many cases where the appropriate assumptions cannot be verified to hold. One factor contributing to the misuse of regression is that it can take considerably more skill to critique a model than to fit a model.
The first type of regression analysis was linear regression. The method of least squares was first published by Legendre in 1805 and in 1809 by Gauß. Both used the method to predict the movement of planets around the sun. Gauss published an improved method in 1821.
Forensic science
Forensic science (or forensics) is when different fields of science work together to answer the questions a lawyer would ask. Most often, forensics is about proving that someone was present at a place where a crime was committed. Specialists take "samples" which are later analyzed in a laboratory. Most forensic tests can take from 1 hour to one year, and investigators need to double (and triple) check the answer, so they know that the answer is the right answer. If a forensics team made a mistake the wrong person could be jailed, or they could get into trouble themselves.
Samples commonly taken include fingerprints. People also look for other things that could be used, for example a few hairs (or pieces of skin). Samples like hair or skin can be use for DNA testing, which allows to tell the gender of the person the hair is from, amongst others.
When someone is accused of committing the crime, these pieces of evidence can then be matched up. Then, if they are correct, the person is charged.
Fingerprint
A fingerprint is a trace of a human finger left on a surface. Human fingers have small structures on them (like mountains and valleys). These structures are unique in every human; they can be used as means of identification.
There are many different ways to take fingerprints. Forensic scientists use these techniques to identify a person.
Electronic fingerprint scanners became widespread in the early 21st century.
Physical cosmology
Physical cosmology is a branch of astronomy. It looks at large structures in the universe. It wants to explain how the universe came to be what it is today by using axioms of our current astronomy knowledge.
Ronald Fisher
Sir Ronald Aylmer Fisher FRS (17 February 1890 – 29 July 1962) was an English statistician, evolutionary biologist, and geneticist. He was described as "a genius who almost single-handedly created the foundations for modern statistical science". Richard Dawkins described him as "the greatest of Darwin's successors".
In 1919 Fisher started work at Rothamsted Experimental Station at Harpenden, Hertfordshire, England. Here he started a major study of the extensive collections of data recorded over many years. This resulted in a series of reports under the general title "Studies in crop variation."
This began a period of great productivity. Over the next seven years, he pioneered the principles of the design of experiments and elaborated his studies of the analysis of variance. He studied the statistics of small samples. Perhaps even more important, he began his systematic approach of the analysis of real data as the springboard for the development of new statistical methods.
He began to pay particular attention to the labour involved in the necessary computations, and developed practical methods. In 1925, his first book was published: "Statistical methods for research workers". This went into many editions and translations in later years, and became a standard reference work for scientists in many disciplines. In 1935, this was followed by "The design of experiments," which also became a standard.
His work on the theory of population genetics made him one of the three great figures of that field, together with Sewall Wright and J.B.S. Haldane. He was one of the founders of the neo-Darwinian modern evolutionary synthesis. In addition to founding modern quantitative genetics with his 1918 paper, he was the first to use diffusion equations to attempt to calculate the distribution of gene frequencies among populations.
He pioneered the estimation of genetic linkage and gene frequencies by maximum likelihood methods. His 1950 paper on gene frequency clines is notable as the first application of a computer to biology.
Fisher had a long and successful collaboration with E.B. Ford in the field of ecological genetics. The outcome of this work was the recognition that the force of natural selection was often much stronger than had been appreciated. Many ecogenetic situations (such as polymorphism) were not selectively neutral, on the contrary, they were maintained by the force of selection.
Fisher was the original author of the idea of heterozygote advantage, which was later found to play a frequent role in genetic polymorphism. The discovery of indisputable cases of natural selection in nature was one of the main strands in the modern evolutionary synthesis.
Fisher was an ardent promoter of eugenics, and he held the Chair in Eugenics at University College London from 1933 until he moved to Cambridge University as Professor of Genetics in 1943.
Between 1929 and 1934 the Eugenics Society also campaigned hard for a law permitting sterilisation on eugenic grounds. They believed that it should be entirely voluntary, and a right, not a punishment. They published a draft of a proposed bill, and it was submitted to Parliament. Although it was defeated by a 2:1 ratio, this was viewed as progress, and the campaign continued. Fisher played a major role in this movement, and served in several official committees to promote it.
In 1934, Fisher moved to increase the power of scientists within the Eugenics Society, but was ultimately thwarted by members with an environmentalist point of view, and he, along with many other scientists, resigned.
Fisher wrote three books of great significance.
His book "The Genetical Theory of Natural Selection" was started in 1928 and published in 1930, with a second edition in 1950. He developed ideas on sexual selection, mimicry and the evolution of dominance. He showed that the probability of a mutation increasing the fitness of an organism decreases proportionately with the magnitude of the mutation. He also proved that larger populations carry more variation and have a larger chance of survival. He set forth the foundations of what was to become known as population genetics.
About a third of the book concerned the applications of these ideas to humans, and presented the data available at that time. He presented a theory that attributed the decline and fall of civilizations to the fertility of the upper classes being low. Using the census data of 1911 for Britain, he showed that there was an inverse relationship between fertility and social class. This was partly due, he believed, to the rise in social status of families who were not capable of producing many children but who rose because of the financial advantage of having a small number of children.
Therefore he proposed the abolishment of the economic advantage of small families by instituting subsidies (he called them allowances) to families with larger numbers of children, with the allowances proportional to the earnings of the father. He himself had two sons and six daughters. According to Yates and Mather, "His large family, reared in conditions of great financial stringency, was a personal expression of his genetic and evolutionary convictions".