 harald cramÃ©r (; 25 september 1893 â 5 october 1985) was a swedish mathematician, actuary, and statistician, specializing in mathematical statistics and probabilistic number theory. he was once described by john kingman as "one of the giants of statistical theory".kingman 1986, p. 186. ==biography== ===early life=== harald cramÃ©r was born in stockholm, sweden on 25 september 1893. cramÃ©r remained close to stockholm for most of his life. he entered the university of stockholm as an undergraduate in 1912, where he studied mathematics and chemistry. during this period, he was a research assistant under the famous chemist, hans von euler-chelpin, with whom he published his first five articles from 1913 to 1914.heyde, seneta 2001, p. 439. following his lab experience, he began to focus solely on mathematics. he eventually began his work on his doctoral studies in mathematics which were supervised by the famous hungarian mathematician, marcel riesz, at the university of stockholm. also influenced by g.h. hardy, cramÃ©r's research led to a phd in 1917 for his thesis "on a class of dirichlet series". ===academic professional career=== following his phd, he served as an assistant professor of mathematics at stockholm university from 1917 to 1929. early on, cramÃ©r was highly involved in analytic number theory. he also made some important statistical contributions to the distribution of primes and twin primes. his most famous paper on this subject is entitled "on the order of magnitude of the difference between prime numbers", which provided a rigorous account of the constructive role in which probability applied to number theory.kendall 1986, p. 211. in the late 1920s, cramÃ©r became interested in the field of probability, which at the time was not an accepted branch of mathematics. cramÃ©r knew that a radical change was needed in this field, and in a paper in 1926 said, "the probability concept should be introduced by a purely mathemat
1893_births 1985_deaths 20th-century_mathematicians People_from_Stockholm Probability_theorists Swedish_actuaries Swedish_mathematicians Swedish_statisticians