A statistical procedure that is used to determine the number of required subjects in a study in order to show a significant difference at a predetermined level of significance and size of effect; it is also used to determine the power of a test from the sample size, size of effect, and level of significance. Power, by definition, is the ability to find a statistically significant difference when the null hypothesis is in fact false; power is your ability to find a difference when a real difference exists (Alliance Terminology & Data Resources May 2021)
Glossary Term