Statistical Power Explorer: Interactive Power Calculator for Sample Size and Effect Size
Before discarding a null result in scientific research or clinical trials, it is crucial to understand whether your study was adequately powered to detect a meaningful effect. Use this interactive statistical power calculator to visualize the relationship between sample size, effect size, significance level, and statistical power for your study design.
This free online tool helps researchers plan robust experiments, optimize sample size, and make evidence-based decisions in academic publishing and biomedical research.
How to use:
Adjust the Effect Size (Cohen’s d) slider to match your hypothesis.
Set your Alpha (α) level (standard is 0.05).
Observe how the required sample size changes to achieve 80% power.
Small (0.2)
Medium (0.5)
Large (0.8)
Analysis: To achieve 80% power with an effect size of 0.5, you need approximately 64 participants per group.