Table 2.
True proportion in active control | Non-inferiority bound using 10% margin | Approximate sample size per group assuming 1:1 randomization to new treatment and control required under: | ||
---|---|---|---|---|
Equal effects | 5% benefit | 10% benefit | ||
0.1 | 0.09 | 19,200 | 8,725 | 5,050 |
0.2 | 0.18 | 8,500 | 3,900 | 2,250 |
0.3 | 0.27 | 4,970 | 2,260 | 1,300 |
0.4 | 0.36 | 3,200 | 1,450 | 825 |
0.5 | 0.45 | 2,100 | 1,000 | 550 |
0.6 | 0.54 | 1,440 | 640 | 360 |
0.7 | 0.63 | 930 | 405 | 225 |
Sample sizes calculated using Pass 2008 methods for non-inferiority tests of two independent proportions, using the Z statistic with continuity correction and pooled variance, with a target power of 90% and α level of 0.025.