G*Power is a statistical power analysis program designed to analyze different types of power and compute size with graphics options. It covers many different statistical tests of the F, t, chi-square, and z test families as well as some exact tests.
G*Power provides improved effect size calculators and graphics options, it supports both a distribution-based and a design-based input mode, and it offers five different types of power analyses. G*Power is free.
Changed the behavior of the "X-Y plot for a range of values" which allowed plotting graphs after changing input parameters in the main window without hitting the "Calculate" button which, however, is required to update the "X-Y plot for a range of values" with the new input parameters from the main dialog.