Half-width of CIs for differences in proportions between two groups with given sample size, placebo group, p=0.5 (created with PASS software REF—PASS V.15)

Difference

0.1

0.2

0.3

0.4

0.5

Width

0.398

0.392

0.382

0.337

0.347

The half-width of the 95% CI of the difference in means for continuous outcome will be 0.889 SD.