Table 2. Commonly used statistical description and tests for demographic tables.

Variable	Distribution	Single group	Two groups	Three or more groups
Continuous variable
Describe	Normal	Mean ± SD	Mean ± SD	Mean ± SD
	Non-normal	Median (IQR)	Median (IQR)	Median (IQR)
Inference	Normal	NA	t-test/standard difference/Hodges-Lehmann estimator	F-test
	Non-normal	NA	Wilcoxon rank sum test	Kruskal-Wallis test
Categorical variable
Describe	NA	N (%)	N (%)	N (%)
Inference	NA	NA	Chi-square test/standard difference	Chi-square test

SD, standard deviation; IQR, interquartile range; NA, not applicable; N, number of non-missing value; %, percentage.