Power: Repeated Measures ANOVA

Power depends on effect size, α, number of measurements, subjects, and correlations among repeated measures.

Key Inputs

• Effect size (f)
• α (significance level)
• Measurements per subject
• Sample size

Example

With moderate effect, α=0.05, 4 measurements, n=30, typical power exceeds 0.8 depending on correlation.

FAQs

Sphericity?
Violations affect df and power; consider corrections (Greenhouse–Geisser).

A priori vs post-hoc?
A priori computes required n; post-hoc computes achieved power.