G*Power 3 covers statistical power analyses for many different statistical tests of the
* F test,
* t test,
* Ï2-test and
* z test families and some
* exact tests.
G*Power 3 offers five different types of power analyses:
* A priori (sample size N is computed as a function of power level 1-Î², significance level Î±, and the to-be-detected population effect size)
* Compromise (both Î± and 1-Î² are computed as functions of effect size, N, and an error probability ratio q = Î²/Î±)
* Criterion (Î± and the associated decision criterion are computed as a function of 1-Î², the effect size, and N)
* Post-hoc (1-Î² is computed as a function of Î±, the population effect size, and N)
* Sensitivity (population effect size is computed as a function of Î±, 1-Î², 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.
There is a separate Intel version, as well as a Windows/Vista version. Register for free for info on updates.