G*Power 3

G*Power 3 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,
• χ²-test and
• z test families and some
• exact tests.

G*Power 3 offers five different types of statistical power analysis:

• A priori (sample size N is computed as a function of power level 1-β, significance level α, and the to-be-detected population effect size)
  
• Compromise (both α and 1-β are computed as functions of effect size, N, and an error probability ratio q = β/α)
  
• Criterion (α and the associated decision criterion are computed as a function of 1-β, the effect size, and N)
  
• Post-hoc (1-β is computed as a function of α, the population effect size, and N)
  
• Sensitivity (population effect size is computed as a function of α, 1-β, and N)
  

G*Power 3 provides improved effect size calculators and graphics options. It supports both a distribution-based and a design-based input mode.

G*Power 3 is available for Mac OS X 10.4 and Windows XP/Vista. G*Power 3 is free.

Download G*Power

... 3.0.10 for Mac OS X 10.4 and 10.5 (1.5 MB) [download Intel version] or [download PPC version]
... 3.0.10 for Windows XP or Vista (10 MB) [download] (Windows users: please make sure to choose "unpack with folders" in your unzip tool)

Vía: Link