Karl Pearson and the Chi - squared Test

Karl Pearson was a man of many parts: the applied mathematician who completed Todhunter's History of the Theory of Elasticity; the philosopher of science whom Lenin described as 'this conscientious and honest opponent of materialism' (1970, p. 170); the statistician who espoused the cause of evolution and edited Biometrika for 35 years; the innovator and administrator whose Department became famous and influential; the tireless contributor to the British war effort during 1914-18; the employer who gave scientific work to women at a time when this was exceptional; and the family man who returned to seek his ancestry among the dales of the North York Moors. When Pearson was 33 years of age, his career began to change as a consequence of two events: