The contributions Fisher made included the development of methods suitable for small samples, the discovery of the precise distributions of many sample statistics and the invention of analysis of variance.Fisher received a B.A. in astronomy from Cambridge in 1912. It was his interest in the theory of errors in astronomical observations that eventually led him to investigate statistical problems. He gave up being a mathematics teacher in 1919 to work at the Rothamsted Agricultural Experiment Station where he worked as a biologist and made many contributions to both statistics and genetics. He studied the design of experiments by introducing the concept of randomisation and the analysis of variance, procedures now used throughout the world.
In 1921 he introduced the concept of likelihood. The likelihood of a parameter is proportional to the probability of the data and it gives a function which usually has a single maximum value, which he called the maximum likelihood.
In 1922 he gave a new definition of statistics. It's purpose was the reduction of data and he identified three fundamental problems. These are
(i) specification of the kind of population that the data came from
(ii) estimation and
(iii) distribution.
The contributions Fisher made included the development of methods suitable for small samples, like those of Gosset, the discovery of the precise distributions of many sample statistics and the invention of analysis of variance. He introduced the term maximum likelihood and studied hypothesis testing.
Fisher is considered one of the founders of modern statistics because of his many important contributions.
He came as an outsider to the field of statistics and is among the most
influential scientists of all time.