ASQ Six Sigma Black Belt 2 — Questions and Answers
Question 1: In the Measure phase of DMAIC, which metric represents the number of defects per million opportunities?
- DPMO (Correct answer)
- Cpk
- Sigma level
- RTY
Correct answer: DPMO
DPMO (Defects Per Million Opportunities) is the standard metric used to quantify process defect rates in Six Sigma.
Question 2: A process with a Cpk of 1.33 operates at approximately which sigma level?
- 3 sigma
- 4 sigma (Correct answer)
- 5 sigma
- 6 sigma
Correct answer: 4 sigma
A Cpk of 1.33 corresponds to a 4-sigma process, yielding approximately 6,210 DPMO.
Question 3: Which sampling method ensures every possible sample of a given size has an equal probability of selection?
- Stratified sampling
- Systematic sampling
- Simple random sampling (Correct answer)
- Cluster sampling
Correct answer: Simple random sampling
Simple random sampling gives every possible sample of size n an equal chance of being chosen, minimizing selection bias.
Question 4: In a cause-and-effect (Ishikawa) diagram for a manufacturing defect, which of the following is NOT a standard 'bone' category?
- Machine
- Method
- Measurement
- Market (Correct answer)
Correct answer: Market
The standard 6M categories are Man, Machine, Method, Material, Measurement, and Mother Nature (Environment) — Market is not one of them.
Question 5: What does the term 'tollgate review' refer to in a Six Sigma project?
- A customer satisfaction survey conducted at project end
- A formal phase-gate review where leadership approves advancement to the next DMAIC phase (Correct answer)
- A statistical test to validate measurement system accuracy
- A lean technique to eliminate non-value-added steps
Correct answer: A formal phase-gate review where leadership approves advancement to the next DMAIC phase
Tollgate reviews are structured checkpoints at the end of each DMAIC phase where the team presents findings and obtains sponsor approval to proceed.
Question 6: Which statistical tool is used to determine whether two or more population variances are equal?
- t-test
- Bartlett's or Levene's test (Correct answer)
- Chi-square goodness-of-fit test
- Mann-Whitney U test
Correct answer: Bartlett's or Levene's test
Bartlett's test (for normal data) and Levene's test (for non-normal data) are used to test equality of variances across groups.
Question 7: In Design of Experiments (DOE), what is the purpose of 'blocking'?
- To reduce the number of experimental runs required
- To isolate and control the effect of a known nuisance variable (Correct answer)
- To randomize the order of experimental runs
- To replicate key treatment combinations
Correct answer: To isolate and control the effect of a known nuisance variable
Blocking groups experimental units by a known nuisance factor so its effect can be separated from the treatment effects of interest.
ASQ Six Sigma Black Belt 2
In the Measure phase of DMAIC, which metric represents the number of defects per million opportunities?