Statistics / David Freedman, Robert Pisani, Roger Purves. Freedman, David, Pisani, Robert, joint author. Purves, Roger, joint author. Mathematical statistics. QA276 .F683 1978 519.5 FRS Inculdes index. Includes bibliographical references and index. New York : W . W . Norton, c1980. c1980. 1978 Text xv, 506, A-83 p. : eng