 2. Lets assume that the average level of the PHQ-9 score is about 10 and the mean change in the scores during the follow-up is 3. Lets assume that the standard deviation of PHQ-9 scores is 5. This difference could be expected to be significant with power 85 on significant level 0.05 if the sample size in each group is 27 subjects. Conclusion: Based on these preliminary power calculations, sample size to be used in this study 30a group will be quite sufficient to detect significant within-group changes between baseline and follow-up in the outcome measures. However, this means that the attrition rate of the study should be near 0 . The outcomes of this feasibility study can be used as a guide to estimate a sample size for our future study. 