Statistical Power Visualizer

See how power, Type I & Type II errors change with effect size, sample size, alpha & tails
Effect size (d)0.50
Sample size (n)100
Alpha (α)0.05
Test type
Power (1−β)0.516
Beta (Type II error)0.484
Alpha (Type I error)0.050
n for 80% power193
Adjust sliders, distributions update instantly
Null Alternative α (Type I) β (Type II) Power Critical value
Type I error (α): Rejecting true null, false positive.  |  Type II error (β): Failing to reject false null, false negative.  |  Power (1−β): Probability of detecting a true effect. (Shaded areas correspond to legend)
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