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Faces of Science: C.R. Rao

Mariana Cook’s book, “Faces of Science,” portrays 77 scientists who have made many of the most important discoveries of our time. Each photograph is accompanied by a personal essay written by the scientists. The portraits in this online series are accompanied by excerpts from those essays. For more information, please visit Mariana Cook’s website:

C.R. Rao - Photos and Text ©Mariana Cook “Faces of Science”

I come from a family of six brothers and four sisters. All of them have had good academic careers, most probably thanks to good genes we have inherited from our parents and to good upbringing. According to statistics, the second born has a lower IQ than the first born, the third a lower IQ than the second, and so on. I am the eighth child! However, from my early years, I showed some interest in mathematics. At the age of six, I knew by heart multiplication tables up to 20 by 20, and at eleven I could do complex arithmetical problems mentally. My father thought that these were promising signs to become a good mathematician and encouraged me to study mathematics. I chose mathematics as my major subject when I entered college and graduated with a master’s degree in mathematics. At that time, the Second World War was on, and it was difficult for a mathematician to get a job. After a few months of waiting and frustration, I found an opening for a mathematician in the Army Survey Unit and went to Calcutta for an interview. As luck would have it, I did not get the job, but discovered the Indian Statistical Institute (ISI), founded by a professor of physics, P.C. Mahalanobis. I was told that those who completed the one-year course in statistics there got good jobs immediately. This seemed to be attractive, and I took admissions to the course, which started my association with the ISI that lasted for about 40 years.

To those accustomed to deducing theorums in mathematics from given premises, the method of drawing conclusions from uncertain premises, or generalizing from a sample, which is the subject matter of statistics, might appear as an unsafe game. However, it is the latter that matters in real life and we have to devise ways of using uncertain knowledge to our best advantage. We are taking risks when we choose a partner for life, decide on a particular career, or make an investment. The key to the problem of taking wise decisions under uncertainty lies in quantifying uncertainty and specifying the risk we are willing to take in making a decision. This is the subject matter of statistics, the new discipline conceived and developed in the last century.

C.R. Rao is Professor of Statistics, Emeritus, and Director of the Center for Multivariate Analysis at the Pennsylvania State University. He has been recognized with the U.S. national Medal of Science, and several technical terms have arisen out of his work including “Cramer-Rao inequality” and “Rao’s score test.”

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Mariana Cook

    MARIANA COOK is a fine art photographer whose work is held in numerous institutional and private collections, including The Metropolitan Museum of Art and The Museum of Modern Art, New York City; The J. Paul Getty Museum, Los Angeles; The Museum of Fine Arts, Boston; The Museum of Fine Arts, Houston; Bibliothèque Nationale and Musée d’Art Moderne de la ville de Paris; and the National Portrait Gallery, Washington, DC. Ten books of her work have been published, including the best-selling Fathers and Daughters (1994) and the most recent, Justice: Faces of the Human Rights Revolution (2013). Stone Walls: Personal Boundaries was her first book of landscapes, which was released in 2011 to much acclaim. Her website is