4.1 Identify situations in which the use of parametric and nonparametric techniques is appropriate….

➤ How do I decide which test to use for small samples or skewed data?
Inspect plots and test assumptions first, and consider transformations. If normality fails or outliers dominate, use nonparametric tests like Mann–Whitney U, Wilcoxon signed-rank, or Kruskal–Wallis. You can also use bootstrap or permutation methods to obtain robust inference without strict parametric assumptions.