Lean Six Sigma Green Belt Certification Measurement System Analysis and Gage R&R 1 — Questions and Answers
Question 1: What does MSA stand for in the context of Lean Six Sigma?
- Measurement System Analysis (Correct answer)
- Mean Statistical Assessment
- Measurement Sampling Approach
- Method of Statistical Analysis
Correct answer: Measurement System Analysis
MSA stands for Measurement System Analysis, a structured study that evaluates the accuracy and precision of a measurement system.
Question 2: Which two components of variation does a Gage R&R study measure?
- Accuracy and Precision
- Repeatability and Reproducibility (Correct answer)
- Reliability and Robustness
- Resolution and Range
Correct answer: Repeatability and Reproducibility
Gage R&R measures Repeatability (variation from the same operator and gage on the same part) and Reproducibility (variation between different operators).
Question 3: Repeatability in a Gage R&R study is defined as the variation observed when:
- Different operators measure the same part
- Different parts are measured by the same operator
- The same operator measures the same part multiple times with the same gage (Correct answer)
- Environmental conditions change during measurement
Correct answer: The same operator measures the same part multiple times with the same gage
Repeatability captures equipment variation — it is the variation seen when one operator repeatedly measures the same part with the same gage.
Question 4: What is the primary purpose of conducting a Gage R&R study in the Measure phase?
- To calibrate measuring instruments to a national standard
- To determine whether the measurement system can detect real process variation (Correct answer)
- To train operators on correct measurement techniques
- To compare the performance of different measurement instruments
Correct answer: To determine whether the measurement system can detect real process variation
Gage R&R determines whether measurement system error is small enough relative to process variation to allow valid data collection and analysis.
Question 5: What %Gage R&R value is generally considered acceptable according to AIAG guidelines?
- Less than 10% (Correct answer)
- Less than 30%
- Less than 50%
- Less than 70%
Correct answer: Less than 10%
A measurement system with %Gage R&R below 10% is considered acceptable, meaning measurement error is a small fraction of total observed variation.
Question 6: Which metric in Gage R&R indicates how many distinct groups a measurement system can reliably differentiate?
- Gage bias
- Number of Distinct Categories (NDC) (Correct answer)
- Stability index
- Linearity coefficient
Correct answer: Number of Distinct Categories (NDC)
The Number of Distinct Categories (NDC) indicates how many separate groups the measurement system can reliably discriminate; an NDC of 5 or more is generally required.
Question 7: Bias in a measurement system is best defined as:
- Inconsistency in measurements between different operators
- The difference between the observed average measurement and the known reference (true) value (Correct answer)
- Variation in measurements taken at different points across the measurement range
- The smallest detectable difference the gage can resolve
Correct answer: The difference between the observed average measurement and the known reference (true) value
Bias is the systematic offset between the average measured value and the true reference value, indicating a consistent over- or under-reading.
Lean Six Sigma Green Belt Certification Measurement System Analysis and Gage R&R 1
What does MSA stand for in the context of Lean Six Sigma?