Anil Kumar Bhattacharyya
Anil Kumar Bhattacharyya () (1 April 1915 – 17 July 1996) was an Indian statistician who worked at the Indian Statistical Institute in the 1930s and early 40s. He made fundamental contributions to multivariate statistics, particularly for his measure of similarity between two multinomial distributions, known as the Bhattacharyya coefficient, based on which he defined a metric, the Bhattacharyya distance. This measure is widely used in comparing statistical samples in biology, physics, computer science, etc. Distance between statistical distributions had been addressed in 1936 by Mahalanobis, who proposed the D metric, now known as Mahalanobis distance. Subsequently, Bhattacharyya defined  a cosine metric for distance between distributions, in a Calcutta Mathematical Society paper in 1943, expanding on some of the results in another paper in Sankhya in 1946. Bhattacharyya's two major research concerns were the measurement of divergence between two probability distributions and the setting of lower bounds to the variance of an unbiased estimator. Life. Bhattacharyya was born to Bhavanath and Lilavati, sometime in March–April 1915 (in the month Chaitra Bengali: চৈত্র of the year 1321, the exact date is not known) at Bhatpara in the district of 24 Parganas of West Bengal. He passed the Matriculation  Examination of Calcutta University in 1932 and I. Sc. Examination in 1934 from Hooghly Mohshin College. In 1936 he ranked first in the First Class at the B.A./B.Sc. examination from the same college and went over to the renowned Science College, Calcutta University for an M.Sc. in Mathematics. Here he had F. W. Levi and Raj Chandra Bose as his teachers and passed the M.A. Examination in 1938 with the first rank in the First Class. In 1939, at Levy's suggestion, Bhattacharyya met P. C. Mahalanobis and joined Indian Statistical Institute as an honorary worker. In 1941, he was  made a part-time lecturer in the newly formed Statistics Department of Calcutta University, headed by Mahalanobis. Here he had C. R. Rao, H. K. Nandi and T. P. Choudhury, as his students. He went to Patna to take up the job of Statistical Officer of Bihar Government, in December 1943 and, in 1946, he returned to Calcutta to join Indian Statistical Institute as Superintending Statistician (in charge of training). Mahalanobis requested him to concurrently take classes in the Statistics Department of Presidency College. After the post was created, Bhattacharyya was made a whole-time Senior Professor and Head of  the Department in 1949. He occupied the post of Senior Professor until his retirement in March 1974, but in 1967 he stepped down from the leadership, apparently piqued by certain moves of the West Bengal Government's Education Department. Almost since his retirement from Government service, he had been associated with the Narendrapur Ramakrishna Mission Residential College as a guest teacher, where a Memorial Scholarship is awarded in his name.