G*Power 3 is a major extension of, and improvement over, G*Power 2 . It covers statistical power analyses for many different statistical tests like:
F test,
t test,
χ2-test and
z test families and some
exact tests

G*Power is offering five different types of statistical power analysis:
· A priori (sample size N is computed as a function of power level 1-ß, significance level a, and the to-be-detected population effect size)
· Compromise (both a and 1-ß are computed as functions of effect size, N, and an error probability ratio q = ß/a)
· Criterion (a and the associated decision criterion are computed as a function of 1-ß, the effect size, and N)
· Post-hoc (1-ß is computed as a function of a, the population effect size, and N)
· Sensitivity (population effect size is computed as a function of a, 1-ß, 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.

What's New in This Release: [ read full changelog ]

· Fixed a bug in the ANCOVA module. Changing the number of covariates now correctly leads to the appropriate change in the denominator degrees of freedom.