Karl Pearson (1857-1936), British statistician. Pearson studied mathematics at Cambridge and afterwards physics and biology in Germany. In 1884 he became professor of mathematics at University College, London. Pearson was particularly brilliant at applying statistical methods to biological problems. In 1900 he developed the chi square test, a criterion to measure the extent to which a theoretical probability distribution fits a set of data. Pearson founded the statistics journal 'Biometrika' with Weldon and Galton in 1901.