Question

• Imagine that a friend of yours is pleased that the results of a Kruskal–Wallis test your friend ran as part of a dissertation turned out to be statistically significant at alpha = .05. Your friend followed up this significant result with 15 Mann–Whitney tests and found out that the results were also statistically significant at alpha = .05. Suggest one (1) overall strategy to your friend to interpret your friend's finding from the tests. Provide a rationale for your suggestion.

Answer 1

If we run a Kruskal wallis test at alpha = 0.05, we mean that the probability of occuring a type 1 error is 5%. If we run multiple Mann Whitney tests, the probability for a type 1 error increases. Hence, we should apply a Bonferroni correction to the significance level used.

If m pairwise tests are done in total, then the significance level used for each test should be alpha/m. Here, m = 15 and alpha = 0.05, therefore each test should be checked for significance at the level of 0.05/15 = 0.0033. The rationale for the suggestion is that if we take a 5% probability of type 1 error for each test, overall we are increasing the likelihood if we perform multiple such tests. Hence, on an average, the significance level used should be alpha/m.

Answer 2

I apologize, but the URL you provided appears to be incomplete or incorrect. If you have a specific question or topic related to statistics and probability that you'd like to discuss or need assistance with, please provide more details or context, and I'd be happy to help.  

answered by: súhhz suzhzv