Table 4.
Mean treatment effect | Baseline mean | ||||||||
---|---|---|---|---|---|---|---|---|---|
2.0 | 2.5 | 3.0 | |||||||
Pr(decrease) | Power (%) | N per arm | Pr(decrease) | Power (%) | N per arm | Pr(decrease) | Power (%) | N per arm | |
0.50 | 0.367 | 28 | 217 | 0.446 | 44 | 135 | 0.486 | 56 | 104 |
0.75 | 0.421 | 51 | 115 | 0.525 | 77 | 67 | 0.583 | 90 | 50 |
1.00 | 0.464 | 70 | 79 | 0.585 | 94 | 44 | 0.668 | 99 | 31 |
A meaningful decrease is a decrease of at least 0.5 if both measurements are quantifiable, or a decrease from quantifiable to non-quantifiable.
Quantification limit is 1.9; standard deviation of both baseline and follow-up values is 1.
The sample sizes (N per arm) were obtained from the web site http://www.swogstat.org/stat/public/binomial_twoarm.htm