Certified Six Sigma Black Belt Exam Free Certified Six Sigma Black Belt Practice Questions and Answers 2 — Questions and Answers
Question 1: A Black Belt discovers that a critical process metric follows a non-normal distribution. Which tool is most appropriate for determining process capability?
- Box-Cox transformation followed by normal capability analysis
- Johnson transformation
- Non-normal capability analysis using Weibull or other fitted distribution (Correct answer)
- Ignoring non-normality and using standard Cp/Cpk calculations
Correct answer: Non-normal capability analysis using Weibull or other fitted distribution
When data is non-normal, fitting an appropriate distribution such as Weibull allows accurate capability analysis without forcing normality assumptions.
Question 2: During the Analyze phase, a team identifies multiple potential root causes. Which technique best helps prioritize these causes based on both probability and impact?
- Pareto chart
- Failure Mode and Effects Analysis (FMEA) (Correct answer)
- Fishbone diagram
- 5 Whys analysis
Correct answer: Failure Mode and Effects Analysis (FMEA)
FMEA systematically evaluates each potential failure mode by severity, occurrence, and detection to produce a Risk Priority Number for prioritization.
Question 3: What is the primary purpose of a Gage R&R study in a Six Sigma project?
- To calibrate measurement instruments to national standards
- To assess the variation contributed by the measurement system relative to total process variation (Correct answer)
- To determine the accuracy of a single measurement device
- To validate that operators are following standard work procedures
Correct answer: To assess the variation contributed by the measurement system relative to total process variation
Gage R&R quantifies how much of the observed process variation is attributable to the measurement system, including both repeatability and reproducibility components.
Question 4: A Black Belt is designing an experiment with 5 factors, each at 2 levels, but resources allow only 8 runs. Which design is most appropriate?
- Full factorial design
- 2^(5-2) fractional factorial design (Correct answer)
- Central composite design
- Plackett-Burman design with 12 runs
Correct answer: 2^(5-2) fractional factorial design
A 2^(5-2) fractional factorial design reduces the full 32-run experiment to 8 runs while still estimating main effects, though some interactions will be confounded.
Question 5: In a hypothesis test comparing two population means, a Black Belt obtains a p-value of 0.03 with alpha set at 0.05. The practical significance is negligible. What should the Black Belt conclude?
- Reject the null hypothesis and implement changes immediately
- Fail to reject the null hypothesis since practical significance is absent
- Report statistical significance but recommend no action due to lack of practical significance (Correct answer)
- Increase the sample size to confirm the result
Correct answer: Report statistical significance but recommend no action due to lack of practical significance
Statistical significance alone does not justify action; a Black Belt must also evaluate whether the difference is large enough to matter practically before recommending changes.
Question 6: Which of the following best describes the purpose of a control plan in the Control phase?
- To document the statistical tests used during the Analyze phase
- To provide a living document that specifies monitoring methods, reaction plans, and responsibilities for sustaining improvements (Correct answer)
- To create a project charter for the next DMAIC cycle
- To train all employees on Six Sigma methodology
Correct answer: To provide a living document that specifies monitoring methods, reaction plans, and responsibilities for sustaining improvements
A control plan documents what to monitor, how to monitor it, acceptable limits, and what actions to take when the process goes out of control to sustain gains.
Certified Six Sigma Black Belt Exam Free Certified Six Sigma Black Belt Practice Questions and Answers 2
A Black Belt discovers that a critical process metric follows a non-normal distribution.
Which tool is most appropriate for determining process capability?