IASSC Certified Lean Six Sigma Black Belt (ICBB) — Question 58

Which of the following non parametric tests is appropriate for testing the equality of population medians for two or more population?

Answer options

• A. Mann-Whitney test
• B. Kruskal-Wallis test
• C. Friedman test
• D. Runs test

Correct answer: A

Explanation

The correct answer is the Mann-Whitney test, which is used to compare the medians of two independent samples. However, for comparing the medians of two or more populations, the appropriate test is actually the Kruskal-Wallis test (option B), making the original answer incorrect. The Friedman test (option C) is used for related samples, and the Runs test (option D) is used for sequence analysis, not for comparing medians.