Course TopicsPower analyses and sample size calculations are important parts of many research projects. Often, before data are even collected, it is necessary to calculate and justify the required ...

In view of the fact that the sample size needed for a specified power does not vary linearly with effect size, the traditional approach typically leads to less power than is desired for the specified ...

Conventionally, sample size calculations are viewed as calculations determining the right number of subjects needed for a study. Such calculations follow the classical paradigm: "for a difference X, I ...

G*Power to the People Several years ago, German researchers developed free software, called G*Power, that calculates sample size. Every scientist should use it. Let's pretend that we are doing a study ...