Statistical power is the likelihood that a statistical test will:
Power can range between 0 and 1, with higher values indicating a greater likelihood of detecting an effect.
What is statistical power?Edit
Statistical power is the probability of correctly rejecting a false H0 (i.e., getting a significant result when there is a real difference in the population).
- Power ≥ .80 generally considered desirable
- Power ≥ .60 is typical of studies published in major psychology journals
Power will be higher when the:
- effect size (ES) is larger
- sample size (N) is larger
- critical value (α) is larger
Statistical power can be calculated prospectively and retrospectively.
If possible, calculate expected power before conducting a study, based on:
- Estimated N,
- Critical α,
- Expected or minimum ES (e.g., from related research)
Report actual power in the results.
Try searching using terms such as "statistical power calculator" and maybe also the type of test, and you should turn up links to useful pages such as:
- Cohen, J. (1992). Power primer. Psychological Bulletin, 112, 155-159.
|Search for Statistical power on Wikipedia.|