Lean Six Sigma Green Belt Certification DMAIC: Measure Phase Tools 2 — Questions and Answers
Question 1: A process capability study yields Cpk = 0.65. What does this indicate?
- The process is highly capable and centered
- The process is not capable and may be off-center (Correct answer)
- The process meets the Six Sigma standard
- The process has no variation
Correct answer: The process is not capable and may be off-center
A Cpk below 1.0 indicates the process is not capable of consistently producing output within specification limits, and the offset from center makes it worse than Cp alone would suggest.
Question 2: Which gauge R&R metric specifically measures the variation contributed by different appraisers?
- Repeatability
- Reproducibility (Correct answer)
- Discrimination ratio
- Percent tolerance
Correct answer: Reproducibility
Reproducibility captures the variation in measurements attributed to different operators (appraisers) measuring the same parts.
Question 3: In a measurement system analysis, a %Gage R&R of 28% is found. What action is most appropriate?
- Accept the measurement system as fully adequate
- Reject all data collected and restart
- Investigate improvement but proceed with caution (Correct answer)
- Immediately replace all measuring instruments
Correct answer: Investigate improvement but proceed with caution
A %Gage R&R between 10% and 30% is considered marginally acceptable; the team should work to improve the system but can proceed cautiously for some decisions.
Question 4: What is the primary purpose of a process map in the Measure phase?
- To identify root causes of defects
- To document current process flow and identify measurement points (Correct answer)
- To establish future-state process design
- To calculate sigma level
Correct answer: To document current process flow and identify measurement points
In the Measure phase, process maps document the current state workflow and help identify where in the process data should be collected.
Question 5: A run chart shows a sequence of 8 consecutive points all above the median. This is an example of:
- Common cause variation
- A run signal indicating special cause (Correct answer)
- Normal random variation
- A trend pattern
Correct answer: A run signal indicating special cause
Eight or more consecutive points on the same side of the median is a run signal, indicating a non-random (special cause) pattern in the data.
Question 6: Which sampling method ensures every possible sample of a given size has an equal probability of being selected?
- Stratified sampling
- Systematic sampling
- Simple random sampling (Correct answer)
- Convenience sampling
Correct answer: Simple random sampling
Simple random sampling gives every possible combination of the desired sample size an equal chance of selection, providing an unbiased representation of the population.
Question 7: When constructing a histogram for Measure phase analysis, what does the shape of the distribution primarily reveal?
- The root cause of defects
- The nature and pattern of process variation (Correct answer)
- The exact sigma level of the process
- The correlation between two variables
Correct answer: The nature and pattern of process variation
Histogram shape reveals whether the data is normal, skewed, bimodal, or otherwise distributed, giving insight into the nature of process variation.
Lean Six Sigma Green Belt Certification DMAIC: Measure Phase Tools 2
A process capability study yields Cpk = 0.65.
What does this indicate?