Lean Six Sigma Black Belt Certification Assessment 2 — Questions and Answers
Question 1: Which measurement system analysis (MSA) statistic indicates the proportion of total variation attributable to the measurement system itself?
- %Contribution (Correct answer)
- Number of Distinct Categories
- Bias
- Linearity
Correct answer: %Contribution
%Contribution from MSA (Gage R&R) shows what fraction of total observed variation is due to the measurement system rather than part-to-part variation.
Question 2: A Black Belt performs a Gage R&R study and finds the Number of Distinct Categories (ndc) is 2. What does this indicate?
- The gage can only distinguish good parts from bad parts (Correct answer)
- The gage is highly capable for process control
- The gage has excellent repeatability
- The gage meets AIAG standards for attribute data
Correct answer: The gage can only distinguish good parts from bad parts
An ndc of 1 or 2 means the gage can barely distinguish two categories (pass/fail), making it inadequate for process monitoring; ndc ≥ 5 is generally required.
Question 3: In a process capability study, a Cpk of 0.85 with a Cp of 1.40 tells the Black Belt what about the process?
- The process is centered well within spec but has high variation
- The process is capable but significantly off-center (Correct answer)
- The process meets Six Sigma quality levels
- The process is both off-center and has excessive spread
Correct answer: The process is capable but significantly off-center
Cp measures potential capability (spread vs. spec width) while Cpk measures actual capability; a high Cp with low Cpk indicates good spread but poor centering.
Question 4: Which type of data collection plan element ensures that samples are collected at the correct time intervals to capture process variation?
- Sampling strategy (Correct answer)
- Operational definition
- Data stratification
- Measurement resolution
Correct answer: Sampling strategy
The sampling strategy specifies when, how often, and how many units to sample to representatively capture the process variation of interest.
Question 5: A team uses a Kano model during assessment. Which category describes features customers do not explicitly request but whose absence causes dissatisfaction?
- Performance needs
- Delighters
- Basic needs (Must-be) (Correct answer)
- Indifferent needs
Correct answer: Basic needs (Must-be)
Basic needs (Must-be or threshold attributes) are expected by customers and their absence causes strong dissatisfaction, but their presence does not increase satisfaction.
Question 6: When conducting a process capability analysis on non-normal data, which transformation is most commonly applied before calculating Cp and Cpk?
- Box-Cox transformation (Correct answer)
- Z-score standardization
- Log-log transformation
- Empirical CDF transformation
Correct answer: Box-Cox transformation
The Box-Cox power transformation family is routinely used to normalize skewed process data so that standard capability indices remain valid.
Question 7: In a multi-vari study used during the Measure phase, which variation source is examined by comparing measurements taken consecutively within a single unit or run?
- Within-piece variation (Correct answer)
- Piece-to-piece variation
- Time-to-time variation
- Operator-to-operator variation
Correct answer: Within-piece variation
Within-piece variation captures differences within a single part or unit (e.g., taper in a machined bore), which is one of three classical multi-vari families.
Lean Six Sigma Black Belt Certification Assessment 2
Which measurement system analysis (MSA) statistic indicates the proportion of total variation attributable to the measurement system itself?