Lean Six Sigma Black Belt Certification Define and Measure Phases 3 — Questions and Answers
Question 1: In a Gage R&R crossed study, which variance component specifically measures variation caused by different appraisers measuring the same part differently?
- Repeatability
- Reproducibility (Correct answer)
- Part-to-part variation
- Linearity
Correct answer: Reproducibility
Reproducibility is the variation in measurements caused by different operators or appraisers measuring the same part.
Question 2: A Voice of the Customer exercise yields the requirement 'deliveries must always be on time.' After applying QFD, what does this become in measurable terms?
- Critical to Quality (CTQ) characteristic (Correct answer)
- Critical to Cost (CTC) characteristic
- Key Process Input Variable (KPIV)
- Defect definition
Correct answer: Critical to Quality (CTQ) characteristic
VOC statements are translated into specific, measurable CTQ characteristics that define what 'quality' means to the customer.
Question 3: Which data collection strategy involves observing and recording process events as they occur in real time rather than from historical records?
- Retrospective data collection
- Prospective (real-time) data collection (Correct answer)
- Stratified sampling
- Cluster sampling
Correct answer: Prospective (real-time) data collection
Prospective data collection captures data as events happen, reducing recall bias and data integrity issues common with historical data.
Question 4: A process produces 3.4 defects per million opportunities. How many sigma does this correspond to, assuming a 1.5-sigma long-term shift?
- 3 sigma
- 4 sigma
- 5 sigma
- 6 sigma (Correct answer)
Correct answer: 6 sigma
3.4 DPMO is the benchmark for a Six Sigma process, which assumes a 1.5-sigma shift from the short-term mean to the long-term mean.
Question 5: When defining project boundaries in the charter, what term describes the point where the process under study begins?
- Process output
- Project goal
- Start point / process trigger (Correct answer)
- Critical to Quality
Correct answer: Start point / process trigger
The start point or trigger event defines where the process begins, which is essential for establishing the project scope boundaries.
Question 6: A team uses a Pareto chart during the Measure phase. What principle does this tool visually demonstrate?
- Normal distribution of defects
- 80/20 rule — vital few vs. trivial many (Correct answer)
- Correlation between two variables
- Process stability over time
Correct answer: 80/20 rule — vital few vs. trivial many
Pareto charts illustrate the 80/20 rule by ranking categories so teams can focus on the vital few causes responsible for most defects.
Question 7: A Black Belt calculates the process sigma level using a Z-table. Which term describes the area under the curve beyond the specification limit?
- Confidence interval
- Defect probability (tail area) (Correct answer)
- Process capability index
- Control limit
Correct answer: Defect probability (tail area)
The tail area (probability in the tail of the normal distribution) beyond the spec limit represents the probability of producing a defect.
Lean Six Sigma Black Belt Certification Define and Measure Phases 3
In a Gage R&R crossed study, which variance component specifically measures variation caused by different appraisers measuring the same part differently?