The article discusses different nonparametric tests like Mann-Whitney U, Kruskal-Wallis, sign test, Wilcoxon signed-rank, and Friedman test. These tests help compare data without assuming a specific distribution. Mann-Whitney U test checks if two samples come from the same population. Kruskal-Wallis test is used for multiple independent samples instead of ANOVA. Wilcoxon signed-rank test focuses on the size of differences between pairs.