Power for one-way ANOVA analysis.

Among number of groups, sample size, effect size, significance level, and power, one and only one can be left blank.

How many groups in the ANOVA analysis?

Provide the number of participants. Multiple sample sizes can be provided in two ways. First, multiple sample sizes can be supplied separated by white spaces, e.g., 100 150 200 will calculate power for the three sample sizes. A sequence of sample sizes can be generated using the method s:e:i with s denoting the starting sample size, e as ending sample size, and i as the interval. For example, 100:150:10 will generate a sequence 100 110 120 130 140 150.

By default, the sample size is 100.

One of Sample size can be specified with multiple values.

The effect size can be calculated based on the effect size calculator.

The effect size to be used. Multiple effect sizes or a sequence of effect sizes can be supplied using the same method for sample size. By default, the value is 0.5.

The effect size can be calculated from proportion by clicking the “Show” button and then inputting the proportion directly.

The significance level (Type I error rate) for power calculation withe the default 0.05.

The power of the test.

Specifying the alternative hypothesis, can be “two.sided” (default), “greater” or “less”

Whether to generate the power curve.

A note (less than 200 characters) can be provided to provide basic information on the analysis.

Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Hillsdale,NJ: Lawrence Erlbaum.