G*Power 3.0.5

G*Power is a major extension of, and improvement over, G*Power 2 . It covers statistical power analyses for many different statistical tests of the
• F test,
• t test,
• ?2-test and
• z test families and some
• exact tests.
G*Power is a nery usetul program that offers five different types of power analyses:
- A priori (sample size N is computed as a function of power level 1-?, significance level ?, and the to-be-detected population effect size)
- Compromise (both ? and 1-? are computed as functions of effect size, N, and an error probability ratio q = ?/?)
- Criterion (? and the associated decision criterion are computed as a function of 1-?, the effect size, and N)
- Post-hoc (1-? is computed as a function of ?, the population effect size, and N)
- Sensitivity (population effect size is computed as a function of ?, 1-?, and N)
G*Power 3 provides improved effect size calculators and graphic options. It supports both a distribution-based and a design-based input mode.
G*Power 3 is available for MacOS X 10.4 and Windows XP/Vista. G*Power 3 is free.