More than 1 sample in each individual
Number of samples in each individual:
2
PASS 11 software was used with a one-sided paired Wilcoxon Signed-Rank test to calculate the sample size. The study power was 90% and the margin of error was 5%. Using the data of the study by William et al. (Ablative fractional CO2 resurfacing for photoaging of the hands: pilot study of 10 patients), the mean and variance of the improvement in wrinkles, pigmentation, and texture of the evaluator and the patient were calculated. Considering an average of 1.5 units of desirable change in improvement, the maximum sample size based on the numbers obtained from the evaluation of the patients' wrinkle level was calculated to be 1.05±2.7 units, equivalent to 10 people.