Statistical Analyses
Statistical analyses were performed using SPSS Statistics for Macintosh (version 25.0; IBM Corp). The baseline characteristics of the study population were expressed as mean and SD for quantitative variables. For the primary outcome of this study, the mean sleep duration at week 4 of the intervention and the means and SDs of sleep duration were calculated at both the baseline data collection period and at week 4 of the intervention period. For the primary end point, a 2-sided paired 