G*Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences
G*Power (Erdfelder, Faul, Buchner, 1996) was designed as a general stand alone power analysis program for statistical tests commonly used in social and behavioral research. G*Power 3 is a major extension of, and improvement over, the previous versions. It runs on widely used computer platforms (i.e. Windows XP, Windows Vista, and Mac OS X 10.4) and covers many different statistical tests of thet, F, and kh2 test families. In addition, it includes power analyses forz tests and some exact tests. G*Power 3 provides improved effect size calculators and graphic options, supports both distribution based and design based input modes, and offers all types of power analyses in which users might be interested. Like its predecessors, G*Power 3 is free.
Behavior research methods