Certified Six Sigma Black Belt Exam Measurement System Analysis (MSA) 4 — Questions and Answers
Question 1: The smallest input change that a measuring device can detect and display is known as the gauge's:
- Accuracy
- Discrimination (resolution) (Correct answer)
- Linearity
- Sensitivity
Correct answer: Discrimination (resolution)
Discrimination (also called resolution or smallest readable unit) is the smallest detectable increment that the measurement device can resolve.
Question 2: According to AIAG MSA guidelines, the measurement device's resolution (discrimination) should be at most what fraction of the process variation or tolerance?
- 1/10 (Correct answer)
- 1/4
- 1/2
- 1/20
Correct answer: 1/10
The gauge's smallest readable increment should be no greater than 1/10 of either the process variation (6σ) or the engineering tolerance to ensure adequate discrimination.
Question 3: In a Type 1 Gauge Study, which two key statistics are primarily evaluated?
- Cg and Cgk (Correct answer)
- %GRR and NDC
- Cp and Cpk
- Kappa and Kendall's tau
Correct answer: Cg and Cgk
A Type 1 Gauge Study evaluates Cg (gauge capability) and Cgk (gauge capability considering bias) by having a single operator measure a reference part multiple times.
Question 4: If operator-by-part interaction is found to be statistically significant in an ANOVA Gauge R&R, what is the most likely root cause?
- The gauge has poor repeatability on all parts equally
- Operators use inconsistent techniques that affect certain parts differently (Correct answer)
- All operators have identical biases
- The parts selected do not span the process variation
Correct answer: Operators use inconsistent techniques that affect certain parts differently
A significant operator-by-part interaction means that operators rank or measure parts differently from each other, suggesting non-uniform operator technique or part-handling differences.
Question 5: A measurement system evaluation shows σ²_total = 1.00, σ²_part = 0.85, σ²_GRR = 0.15. What is the %GRR (study variation method, using variance)?
- 8.5%
- 15% (Correct answer)
- 17.6%
- 85%
Correct answer: 15%
%GRR using variance contribution = σ²_GRR / σ²_total × 100 = 0.15/1.00 × 100 = 15%.
Question 6: In an attribute agreement analysis for a go/no-go gauge, 'within-appraiser agreement' measures:
- How consistently one appraiser classifies the same parts across multiple trials (Correct answer)
- How closely different appraisers agree with each other
- How well appraiser classifications match the known standard
- The percentage of parts that are borderline cases
Correct answer: How consistently one appraiser classifies the same parts across multiple trials
Within-appraiser agreement (repeatability for attribute systems) evaluates whether a single appraiser makes the same accept/reject decision on the same part across repeated trials.
Question 7: Which action best addresses high Reproducibility (operator-to-operator variation) found in a Gauge R&R study?
- Calibrate the gauge more frequently
- Replace the gauge with one of finer resolution
- Standardize operator training and written measurement procedures (Correct answer)
- Increase the number of parts used in the study
Correct answer: Standardize operator training and written measurement procedures
High reproducibility variance indicates operators are measuring differently, so standardizing procedures and training corrects the root cause directly.
Certified Six Sigma Black Belt Exam Measurement System Analysis (MSA) 4
The smallest input change that a measuring device can detect and display is known as the gauge's: