Statistical analysis. vestibule mean pain score of 8.0 1.4,13 we estimated by using a two-sample t test that a sample size of 44 would achieve 94% power to detect at least 1.5 points mean difference in pain scores between treatment and placebo. We made adjustments on the basis of the asymptotic relative efficiency (ARE) of the Mann-Whitney U test relative to the t test, assuming a non normal underlying distribution, and confirmed that the given sample size of 44 still achieved more than 90% power. Allowing for a dropout rate of 5%, 46 participants were needed for randomization. Characteristics of randomized groups were analyzed by using a t test or Mann-Whitney U test, depending on the distribution for continuous variables. Categorical variables were analyzed by 2 or Fisher's exact test. Comparisons of reported numeric rating scale or Female Sexual Distress Scale values used the two-tailed Mann-Whitney U test, and patients' changes in those scales were tested by using two-tailed Wilcoxon signed rank test, each with significance set at P < .05.

Hint- This was a hypothesis issue, NOT a confidence interval issue.

Q3: This is a hypothesis testing study, and the test power and sample size were specified even before the trial started. In the above analysis, they estimated a sample size of 44 (the total of both groups) would achieve 94% power to detect a minimum of 1.5 points mean difference in pain scores between treatment and placebo.

• If we keep every estimate the same (the expected minimal difference in mean, the standard deviation, and the significance level of 0.05), how many patients would be required to recruit to achieve 80% and 90% power, respectively? Assuming the attrition is 0%.