Healey, Joseph F. Statistics : a tool for social research - 7th ed. - Australia; USA: Thomson/Wadsworth, 2005. - xx, 556p.;25cm "N" ISBN: "0-534-62810-9" Subjects--Topical Terms: 1.Social sciences -Statistical methods 2. Statistics. Subjects--Index Terms: "Y" LC Class. No.: HA29 / .H39