Introductory statistics for the behavioral sciences Joan Welkowitz, Robert B. Ewen [and] Jacob Cohen. Welkowitz, Joan. Ewen, Robert B., 1940- joint author. Cohen, Jacob, 1923-1998, joint author. Psychometrics. BF39 .W44 1971 510 WEI New York, Academic Press 1971. 1971. 1971 Text xvi, 271 p. : eng