IASSC Certified Lean Six Sigma Black Belt (ICBB) — Question 32

Identify the incorrect statement.

Answer options

• A. Parametric method uses the normality assumption
• B. Non parametric method does not use any normality assumptions
• C. Non parametric test results are more robust against violation of assumptions
• D. Non parametric tests provide greater power than parametric tests with equal sample sizes when assumptions are met

Correct answer: B

Explanation

Option B is incorrect because non-parametric methods can still have assumptions, albeit different from parametric methods. The other options are accurate since parametric methods do operate under normality assumptions, non-parametric tests are generally more robust to assumption violations, and under certain conditions, non-parametric tests can provide lower power than parametric tests.