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Sample Size Calculator (web)

2 group means repeated measures - Hypothesis Testing

Standard deviation (σ):
Expected difference:
Number of repeated measurements (r):
Correlation between repetitions (ρ):
A value between 0.6 to 0.75 is common (Machin et al., 2009)
Use baseline measurement as covariate? Yes No
Choose "Yes" for RM ANCOVA (baseline as covariate), "No" for RM ANOVA
Significance level (α): Two-tailed
Power (1 - β): %
Expected dropout rate: %

Sample size, n per group =
Sample size (with 10% dropout), n_drop per group =

Formula reference:

Machin, D., Campbell, M. J., Tan, S. B., & Tan, S. H. (2009). Sample size tables for clinical studies (3rd ed.). John Wiley & Sons.

Suggested reference:

APA: Arifin, W. N. (). Sample size calculator (web). Retrieved from http://wnarifin.github.io

Vancouver: Arifin WN. Sample size calculator (web) [Internet]. [cited ]. Available from: http://wnarifin.github.io

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