I'm currently pursuing a PhD, but I have only taken one statistics subject, so I would consider my statistical knowledge being basic. I want to compare multiple prototypes that accomplish the same task but differ in some aspects. My goal is to compare task completion time using non-parametric methods, but I am unsure which statistical approach would be appropriate. The study will include participants with special needs, so the sample size will likely be very small (possibly single digits). I will also include other participants, but I believe it makes sense to analyze these groups separately. Because of this, I expect to use a within-subjects design, where participants test multiple prototypes. For my research, I understand that the Wilcoxon signed-rank test may be suitable for comparing two conditions in a within-subjects setting, but I am unsure how to proceed with more than two prototypes.…