Here, we will look at the number of samples needed in a one-way ANOVA to detect differences of 1, 2, or 3 standard deviations in size for 80 or 90 percent power. When we do not have a historical standard deviation, we can use a figure of one in the dialog box. The differences are then referred to as multiples of the standard deviation.
The following steps will generate the sample sizes required to find differences of 1, 2, or 3 standard deviations with at least 80 or 90 percent power:
Navigate to Stat | Power and Sample Size. Then click on One Way ANOVA.
In the Number of levels: field, enter
12.In Values of the maximum difference between means:, enter
1 2 3.In Power values:, enter
.8 .9.In Standard deviation:, enter
1. The dialog box should look like the following screenshot:
Click on OK.