2.8 Sample size calculation
Sample size was determined using the estimates of mean and standard deviation values from literature using the following formula:
For 80% power, (type I error to be 5%, type II error to be 20%) the sample size was calculated to be 128, 64 in each arm, at a two-sided significance level of α = 0.05, for superiority trial and considering 5% drop out rate. The allocation ratio was approximately 1:1.