4.5. Statistical Data Analysis
The Shapiro–Wilks normality test was performed to choose a parametric or non-parametric test for comparisons. Quantitative data are presented as the mean standard deviation (SD) or the median interquartile range [IQR]. Categorical variables are expressed as percentages. The relative frequencies of genotypes were calculated for each group. The observed gene frequencies were compared with expected frequencies using the chi-square test and the Hardy–Weinberg proportion. In all cases, multiple testing was adjusted by the Bonferroni correction method. The demographic, clinical, pharmacological, and genetic data were compared using either the χ