This chapter discusses chi-square tests and nonparametric tests. It begins by introducing contingency tables and how they are used to classify sample observations according to multiple characteristics. Examples are provided to demonstrate how to set up contingency tables and calculate expected frequencies. The chapter then explains how to perform chi-square tests to analyze differences between two or more proportions, test independence between categorical variables, and compare population medians using the Wilcoxon rank-sum test. Decision rules for each test are outlined. Worked examples are provided to demonstrate applying these statistical tests and interpreting the results.