Certified Six Sigma Black Belt Exam Measurement System Analysis 3 — Questions and Answers
Question 1: A Black Belt wants to evaluate whether a measurement system is capable of detecting a shift of 1.5σ in the process. Which MSA metric is most directly relevant?
- Bias
- Linearity
- %Study Variation (%SV) (Correct answer)
- Stability index
Correct answer: %Study Variation (%SV)
%Study Variation compares gage variation to the total process spread, directly indicating whether the gage can detect meaningful shifts.
Question 2: During a Gage R&R ANOVA study, a significant Operator × Part interaction is detected. What does this indicate?
- All operators are measuring with the same bias
- Some operators are better at measuring specific parts than others, suggesting operator technique varies by part (Correct answer)
- The parts have too little variation to conduct a valid study
- Repeatability error is negligible
Correct answer: Some operators are better at measuring specific parts than others, suggesting operator technique varies by part
A significant Operator × Part interaction means operators do not measure all parts consistently relative to each other — certain operators may have difficulty with specific part geometries or sizes.
Question 3: What is the primary purpose of including at least 10 distinct parts in a crossed Gage R&R study?
- To minimize the number of required appraisers
- To ensure the parts represent the full range of the process variation (Correct answer)
- To reduce the time required for the study
- To eliminate the need for a control chart
Correct answer: To ensure the parts represent the full range of the process variation
Parts should span the full process variation so the study reflects real-world measurement conditions and provides a valid estimate of %Study Variation.
Question 4: In a linearity study, a gage shows a slope of +0.08 across the operating range. What does a positive slope indicate?
- Bias increases as the reference value increases (Correct answer)
- Bias decreases as the reference value increases
- The gage has no systematic error
- Repeatability worsens at higher values
Correct answer: Bias increases as the reference value increases
A positive slope in a linearity study means the gage's bias (difference from reference) grows larger as the true value increases.
Question 5: Which of the following scenarios best describes a Type I error in the context of attribute MSA?
- An appraiser passes a defective part (false negative)
- An appraiser rejects a conforming part (false positive) (Correct answer)
- An appraiser agrees with another appraiser on a borderline part
- The measurement system has high discrimination
Correct answer: An appraiser rejects a conforming part (false positive)
A Type I error (producer's risk) occurs when a good part is incorrectly rejected, creating unnecessary scrap or rework.
Question 6: A torque wrench used in assembly is calibrated against a reference standard once per shift. This practice primarily addresses which MSA characteristic?
- Reproducibility
- Linearity
- Stability (Correct answer)
- Resolution
Correct answer: Stability
Periodic calibration checks detect drift over time, which is the definition of monitoring measurement system stability.
Question 7: In a nested (hierarchical) Gage R&R design, parts are not measured by all operators. When is this design necessary?
- When parts are plentiful and inexpensive
- When measurement is destructive or parts cannot be re-measured (Correct answer)
- When the number of operators exceeds 5
- When the tolerance is very tight
Correct answer: When measurement is destructive or parts cannot be re-measured
A nested design is used when parts are destroyed or altered by measurement, making it impossible for all operators to measure the same parts.
Certified Six Sigma Black Belt Exam Measurement System Analysis 3
A Black Belt wants to evaluate whether a measurement system is capable of detecting a shift of 1.5σ in the process.
Which MSA metric is most directly relevant?