What is the appropriate type of analysis (Parametric versus Non-parametric Analysis) for a sample of 21 subjects?

I am comparing 21 subjects´ results (before and after) but I am not sure if this sample requires a T-test (Parametric) or the WILCOXON HODGES_LEHMAN (Non parametric). Someone did the test for...

01 June 2021 6,830 4 View