统计描述在材料与方法中的表达
Continuous variables with normal distribution were represented as the mean ± standard deviation, and compared by Student’s t-test.
连续性变量（计量资料）符合正态性分布的采用均数±标准差表示，采用t检验进行比较
Continuous variables with non-normal distribution were represented by the median (Q1-Q3), and compared using Wilcoxon’s rank-sum test
连续性变量（计量资料）不符合正态性分布的采用中位数（四分位间距）表示，采用Wilcoxon’s 秩和检验进行比较
Categorical variables were represented as frequency (percentage) and compared using the χ2 test.
分类变量采用频数（百分比）表示，采用卡方检验进行比较
