Power Analysis Calculator
Calculate statistical power for hypothesis testing
Small: 0.2, Medium: 0.5, Large: 0.8
Results:
Statistical Power: 49.06%
Type II Error (β): 50.94%
Effect Size (Cohen's d): 0.5
Sample Size (per group): 30
Significance Level (α): 0.05
Interpretation:
Low power. Increase sample size to improve detection probability.
About Statistical Power
Statistical power is the probability of correctly rejecting the null hypothesis when it is false (detecting a true effect).
Power = 1 - β (where β is the Type II error rate)
Commonly accepted standards:
- Minimum acceptable power: 0.80 (80%)
- High power: 0.90 or above
Power increases with larger effect sizes, larger sample sizes, and higher alpha levels.