2.6. Statistical Analysis
Statistical analyses were performed using SPSS Statistics 26 software package (SPSS Inc., Chicago, IL, USA) and Microsoft Excel (Excel version in Microsoft Office 2016 for Windows, Microsoft, WA, USA). The normality of data was examined using the Shapiro–Wilk test. Corresponding two-group comparisons were made using the Wilcoxon signed-rank test. For comparisons between two groups without correspondence, the Mann–Whitney U test was used. Pearson’s correlation analysis was used for correlation analysis. Differences were considered significant at the level of 