Editing Power (statistics) (section)

{{Short description|Term in statistical hypothesis testing}}
In [[frequentist]] [[statistics]], '''power''' is the probability of detecting a given effect (if that effect actually exists) using a given test in a given context. In typical use, it is a function of the specific test that is used (including the choice of test statistic and [[significance level]]), the [[sample size]] (more data tends to provide more power), and the [[effect size]] (effects or correlations that are large relative to the variability of the data tend to provide more power).

More formally, in the case of a simple [[hypothesis test]] with two hypotheses, the '''power of the test''' is the probability that the test correctly rejects the [[null hypothesis]] (<math>H_0</math>) when the [[alternative hypothesis]] (<math>H_1</math>) is true. It is commonly denoted by <math>1-\beta</math>, where <math>\beta</math> is the probability of making a [[Type I and type II errors#Type II error|type&nbsp;II error]] (a [[false negative]]) [[conditional probability|conditional]] on there being a true effect or association.