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Statistics vocabulary · Hypothesis Testing

Statistical power

Meaning in statistics, with examples

nounCommon term

In statistics, statistical power means: The probability that a test will detect an effect when a real effect of a given size exists; it equals one minus the probability of a Type II error.

In Turkish: istatistiksel güç, testin gücü

How it is used

Researchers usually aim for 80% or 90% power. Power increases with a larger sample, a larger effect and a less strict significance level. A power analysis, done before the study with tools such as G*Power, shows how many participants are needed.

Example sentences

  1. The study had 80% statistical power to detect a 5-point difference.

  2. Most of these early studies lacked statistical power, so their null results tell us little.

Common collocations

  • power analysis
  • adequate statistical power
  • underpowered study
  • increase power
  • 80% power
  • type II errorFailing to reject a null hypothesis that is actually false, in other words missing an effect that really exists; a false negative.
  • sample sizeThe number of observations or participants included in a study, usually written as n (or N for the total).
  • effect sizeA number that shows how large a difference or relationship is, independently of sample size, such as Cohen's d, a correlation coefficient or an odds ratio.
  • significance levelThe threshold, chosen before a test, below which a p-value is treated as statistically significant; it is also the accepted risk of a Type I error.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Hypothesis Testing

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