Table 1 Sample size determination
From: HIV, immune activation and salt-sensitive hypertension (HISH): a research proposal
F tests using MANOVA for repeated measures, within–between interaction | ||
|---|---|---|
Options | Pillai V, O’Brien-Shieh Algorithm |  |
Analysis | A priori: Compute sample Size | Â |
Input | Effect size f(v) | 1 |
α err prob | 0.05 | |
Power (1-β err prob) | 0.80 | |
Number of groups | 4 | |
Number of measurements | 3 | |
Output | Non-centrality parameter λ | 22 |
Critical F | 2.8477260 | |
Numerator df | 6.0 | |
Denominator df | 14.0 | |
Sample size | 11 per group | |
Lost to follow (10%) | 1 per group | |
Total sample size | 48 | |
Actual power | 0.825 | |
Pillai V | 1.0 | |