4.4. Statistical Methods
All data were analyzed using Python Software Foundation version 3.8 for Windows (DE, USA). The data were reported as median and inter-quartile range 25–75. The assumption of normality and homoscedasticity was verified using Shapiro–Wilk’s W-test before parametric tests. To identify the magnitude of the statistical difference between sham and IHHE treatments in each period of the study, Fisher’s exact test was used. Because of the non-normal distribution of data, we used Mann–Whitney’s U-test or Wilcoxon’s test to compare the baseline data between the groups as well as different changes (normalized delta pre–post, z-scores) between the groups. Pearson’s or Spearman’s correlation analysis was performed to test relationships between the variables. The a-level was set at 0.05 for all statistical analyses.