# Statistical Power:

Sampling Distributions for PRE

This applet provides a visual representation of statistical power. The red line depicts the sampling distribution of PRE under the null hypothesis. The upper 5% of this distribution, represented by the reddish filled area, defines the critical value for PRE. The blue line depicts the sampling distribution of PRE under the alterative hypothesis for a specified value of eta-sq. The proportion of this distribution above the critical value, represented by the bluish filled area, depicts the statistical power. Change any of the entries in the text boxes to evaluate statistical power for other values of PC, PA, N, and eta-sq. After making the last change, press the RETURN key.

#### Note:

This applet is still a bit fragile. Extreme values for the parameters may break it. And there currently are no appropriateness checks for the parameters (e.g., no check to ensure that PC < PA < N).