2.4. Statistical Analysis

Matched pre-test, post-test, and follow-up surveys were utilized for analysis.A few participants did not complete all questions on the 135 item survey; hence, missing data were excluded from the analysis. Pearson’s chi-square test, paired-sample t-test, McNemar, and ANOVA tests were used to assess change among intervention objectives. Data analysis was conducted using PASW Statistics for Windows, Version 18.0 (SPSS, Inc., 2009, Chicago, IL, USA).

We performed a posthoc retrospective power calculation for sample of 228 participants matched of pre-post and immediate post-test, mean difference 0.5, within group standard deviation 3, and alpha levels 0.05 for paired T test. Our calculation resulted in 70.8% power of this study. Additionally, we calculated a post-hoc retrospective power calculation for matched pre-test, post-test and follow up sample of 110 participants, mean difference 0.8, within group standard deviation 3 and alpha levels 0.05 for paired T test. Data indicate that the difference in the response of matched pairs is normally distributed with standard deviation 3. Our calculation resulted in 79.2% power. We used PS software to calculate power of the study [41].