Radha Laha

Laha, Radha
Born	1 October 1930 Calcutta, India
Died	14 July 1999 Perrysburg, Ohio
Fields	Mathematician, Probabilist, Statistician
Institutions	Indian Statistical Institute, Calcutta Catholic University of America Bowling Green State University
Alma mater	Indian Statistical Institute, Calcutta University
Doctoral advisor	C. R. Rao
Known for	Work in Characteristic Functions, Probability Theory

Radha Govind Laha (1930–1999) was a probabilist, statistician, and mathematician, known for his work in probability theory, characteristic functions, and characterisation of distributions. He was born in Calcutta, India and he was a student of C. R. Rao at Calcutta University, where in 1957 he earned a doctorate in analytical probability theory from the prestigious Indian Statistical Institute. His dissertation was entitled Some Characterization Problems in Probability Theory and Mathematical Statistics.

Laha's primary and secondary education was completed in Calcutta. In 1949 he graduated first in rank with a bachelor's degree in statistics from Presidency College, Calcutta. He earned his master's degree in statistics in 1951, and doctoral degree in analytical probability theory from Calcutta University in 1957. Prizes and awards during this period include the Saradprasad prize, the Duff scholarship, the S.S. Bose Gold Medal, a University of Calcutta Silver Medal, and Fulbright Fellowship in the US

In 1952 Laha joined the staff of the Indian Statistical Institute, Theoretical Research and Training School, Calcutta, India, in pure and applied statistics. In 1958 he was a Research Associate at Catholic University of America in Washington, D.C. He returned to the Indian Statistical Institute for two years, and joined the faculty of Catholic University as a faculty member in 1962. During this period Laha established an international reputation, and he visited statistical institutes at University of Paris, France, ETH Zurich, Switzerland, and in the United States. He moved to Bowling Green State University in 1972, along with his colleagues Eugene Lukacs and Vijay Rohatgi, to start a new PhD program there. Laha retired from Bowling Green State University in 1996 and died in Perrysburg, Ohio on 14 July 1999 after a long illness.

Laha was the author of several classical texts on probability theory and statistics and numerous publications in journals. He was an honoured Fellow of the Institute of Mathematical Statistics and an elected member of the International Statistical Institute. His doctoral students include Bernard McCabe (The Catholic University of America 1967), Thomas O'Connor (Bowling Green State University 1975), and Jeffrey Spielman (Bowling Green State University 1975).

Laha was particularly interested in characterisations of the normal distribution. One of his well known results is his disproof of a long standing conjecture: that the ratio of two independent, identically distributed random variables is Cauchy distributed if and only if the variables have normal distributions. Laha became known for disproving this conjecture. Laha also proved several generalisations of the classical characterisation of normal sample distribution by the independence of sample mean and sample variance.

Laha made a generous endowment from his estate to the American Mathematical Society and the Institute of Mathematical Statistics. The AMS established the Radha G. Laha Gardens in 2001. A portion of the Laha Gardens outside the AMS headquarters in Providence, Rhode Island is identified by a plaque inscribed 'to honour his gift and commitment to mathematical research'. In 2001 with Laha's generous bequest, the Institute of Mathematical Statistics established the Laha Awards to provide travel funds to present a paper at the IMS Annual Meeting.

Journal articles

• Laha, R. G. (1991). A characterisation of Gaussian law in Hilbert space, Aequationes Math. 41 (1991), no. 1, 85–93.