Certified Six Sigma Black Belt Exam Assessment 3 — Questions and Answers
Question 1: A Black Belt conducts a process risk assessment using FMEA. Which combination of RPN factors is used to prioritize failure modes?
- Frequency, Impact, Detectability
- Severity, Occurrence, Detection (Correct answer)
- Probability, Severity, Controllability
- Likelihood, Consequence, Mitigation
Correct answer: Severity, Occurrence, Detection
RPN (Risk Priority Number) = Severity × Occurrence × Detection, with scores on a 1–10 scale for each factor.
Question 2: A measurement system assessment shows a discrimination ratio (DR) of 3. What does this indicate?
- The gauge can detect at least 3 distinct categories of product variation
- The gauge is highly capable with more than 5 distinct categories
- The gauge is inadequate; DR must be at least 5 (Correct answer)
- The gauge resolution is three times the process spread
Correct answer: The gauge is inadequate; DR must be at least 5
A discrimination ratio below 5 indicates the gauge cannot adequately distinguish between parts; a DR ≥ 5 is the minimum acceptable threshold.
Question 3: Which assessment technique involves tracking a single unit or batch through an entire process to identify all value-added and non-value-added steps?
- Time-motion study
- Process walk (Gemba walk)
- Value stream mapping (Correct answer)
- Process FMEA
Correct answer: Value stream mapping
Value stream mapping documents every step, delay, and resource for a product or service family, categorizing each step as value-added or waste.
Question 4: A Six Sigma team is assessing whether a new process has a different mean than the historical mean of 50 units. The sample size is 30 and population variance is unknown. Which test is appropriate?
- Z-test
- One-sample t-test (Correct answer)
- Chi-square test
- F-test
Correct answer: One-sample t-test
With unknown population variance and n=30, a one-sample t-test is used to compare a sample mean against a known historical value.
Question 5: During a process assessment, rolled throughput yield (RTY) is calculated across 4 sub-processes with yields of 95%, 92%, 97%, and 90%. What is the RTY?
- 93.5%
- 76.4% (Correct answer)
- 88.9%
- 81.3%
Correct answer: 76.4%
RTY = 0.95 × 0.92 × 0.97 × 0.90 ≈ 0.764, or approximately 76.4%.
Question 6: A Black Belt wants to assess whether defect rates differ significantly across three production shifts. Which statistical test is most appropriate?
- One-way ANOVA
- Paired t-test
- Chi-square test for independence (Correct answer)
- Kruskal-Wallis test
Correct answer: Chi-square test for independence
A chi-square test for independence compares categorical defect counts across groups (shifts), making it appropriate for this assessment.
Question 7: In capability assessment, what does a Cpm index measure that Cpk does not?
- Process centering relative to specification limits
- Process centering relative to the target value (Correct answer)
- Long-term vs. short-term process variation
- The ratio of tolerance to 6-sigma spread
Correct answer: Process centering relative to the target value
Cpm (Taguchi capability index) penalizes deviation from the nominal target, not just the specification limits, making it target-centric.
Certified Six Sigma Black Belt Exam Assessment 3
A Black Belt conducts a process risk assessment using FMEA.
Which combination of RPN factors is used to prioritize failure modes?