One-Way ANOVA Sample Size Calculator
ProCalculate the sample size needed to compare means across three or more independent groups using an F-test.
Study Parameters
Cohen's f guidelines:
Small: f = 0.10 | Medium: f = 0.25 | Large: f = 0.40
f = sigma_m / sigma, where sigma_m is the SD of group means
Results
Required Sample Size
30129
Group 1: 10043 | Group 2: 10043 | Group 3: 10043
Achieved Power
0.0%
Effect Size
0.250
Method: One-Way ANOVA (F-test approximation)
Per group10043
Number of groups3
Cohen's f0.250
df1 (between)2
df2 (within)30126
- •Independent observations
- •Normally distributed outcomes in each group
- •Equal variances (homoscedasticity) across groups
- •Equal group sizes (balanced design)
Formula
lambda = N * f^2, Power = P(F_{g-1, N-g, lambda} > F_{alpha, g-1, N-g})
References
- Cohen J (1988). Statistical Power Analysis for the Behavioral Sciences, 2nd ed. Erlbaum.