Statistical procedures and their mathematical bases / Charles C. Peters and Walter R. Van Voorhis. Peters, Charles C. (Charles Clinton), 1881-1973. Van Voorhis, Walter Roe, 1904-, author. Statistics. Mathematics. 519 PES "First edition." "This volume is a revision and extension of a book by the same title published privately in lithoprinted form in 1935"--Pref. "References for further study" at end of each chapter except the first." Includes bibliographies and index. New York : McGraw-Hill Book Co., Inc., 1940. 1940. 1940 Text xiii, 516 p. : eng