WISE Power Tutorial
This tutorial is designed to provide a conceptual, non-mathematical, overview of the factors that affect power. You will learn how statistical power is influenced by four features of the test situation: the size of the difference between the actual population mean and the null hypothesized mean (μ1 – μ0); variability of scores within groups (σ); sample size (n); and alpha error (α). Further, you will use an interactive applet that allows you to manipulate features of the test situation and immediately see the effect on statistical power. The mathematics for power calculations are provided at the end of this tutorial.