Lean Six Sigma Green Belt Certification Measurement System Analysis and Gage R&R 2 — Questions and Answers
Question 1: Reproducibility in Gage R&R is best described as:
- Variation from the same operator measuring the same part repeatedly
- Variation caused by using gages from different manufacturers
- Variation caused by different operators measuring the same parts with the same gage (Correct answer)
- Variation due to changing environmental conditions
Correct answer: Variation caused by different operators measuring the same parts with the same gage
Reproducibility captures operator-to-operator variation — it is the variation observed when different operators measure the same parts using the same gage.
Question 2: Linearity in the context of measurement system analysis means:
- The measurement system produces the same result each time it is used
- The bias of the measurement system is consistent across its full operating range (Correct answer)
- Different operators obtain the same measurement results
- The gage has been calibrated against a certified standard
Correct answer: The bias of the measurement system is consistent across its full operating range
Linearity assesses whether the gage's bias remains constant across the full operating range — a non-linear gage has different bias at low versus high measurement values.
Question 3: What is the standard AIAG Gage R&R study design in terms of parts, operators, and replicates?
- 5 parts, 2 operators, 2 replicates
- 10 parts, 3 operators, 2 replicates (Correct answer)
- 20 parts, 5 operators, 3 replicates
- 10 parts, 5 operators, 1 replicate
Correct answer: 10 parts, 3 operators, 2 replicates
The AIAG standard calls for 10 parts, 3 operators, and 2 replicates for a total of 60 measurements, providing sufficient statistical power for the study.
Question 4: Which type of Gage R&R study design is used when parts are destroyed or consumed during measurement?
- Crossed Gage R&R
- Attribute Gage R&R
- Nested Gage R&R (Correct answer)
- Expanded Gage R&R
Correct answer: Nested Gage R&R
Nested Gage R&R is used for destructive testing, where each operator measures a unique set of parts rather than the same parts as the other operators.
Question 5: Stability (drift) in a measurement system refers to:
- The ability of a gage to consistently measure parts across multiple operators
- The change in the measurement system's bias over time when measuring the same reference part (Correct answer)
- The smallest increment the gage can reliably detect
- The consistency of measurements taken at different locations in a facility
Correct answer: The change in the measurement system's bias over time when measuring the same reference part
Stability measures how the gage's bias changes over time; an unstable measurement system drifts, giving different average readings of the same reference part across time.
Question 6: What does the %Tolerance method in Gage R&R analysis compare?
- Operator skill variation as a percentage of total variation
- Measurement system variation as a percentage of the engineering specification tolerance (Correct answer)
- Part-to-part variation as a percentage of total observed variation
- Gage bias as a percentage of the measurement range
Correct answer: Measurement system variation as a percentage of the engineering specification tolerance
The %Tolerance method expresses measurement system variation as a percentage of the specification tolerance, determining whether the gage is fit for inspection use.
Question 7: In which DMAIC phase is a Gage R&R study most commonly conducted?
- Define
- Measure (Correct answer)
- Analyze
- Control
Correct answer: Measure
Gage R&R is conducted in the Measure phase to validate the measurement system before collecting process data, ensuring data integrity for subsequent analysis.
Lean Six Sigma Green Belt Certification Measurement System Analysis and Gage R&R 2
Reproducibility in Gage R&R is best described as: