The English statistician Sir Ronald Aylmer Fisher (1890-1962) introduced fresh ideas into the planning and interpretation of quantitative biological experiments. He was a pioneer in the mathematical theory of genetics.

Ronald Fisher was born in London on Feb. 17, 1890, and was educated at Cambridge University, where he specialized in mathematics and physics. In 1919 he was appointed to the new post of research statistician at the Rothamsted Experimental Station in Hertfordshire. His primary task there was the analysis and reinterpretation of a 66-year backlog of records on continuous agricultural experiments and associated meteorological data. In discharging this duty he revolutionized existing statistical techniques, and he expressed the new outlook in Statistical Methods for Research Workers (1925), which was to become, and to a large extent remains, the bible of applied statistics.

A central theme of Fisher's work in statistics was hypothesis testing. Many experiments, especially biological ones, are essentially devised to...