FREE Lean Six Sigma Black Belt Certification Prep Questions and Answers

Question 1

How is Total Process Variation (t) expressed in terms of Gage (m) and Part (p) Variation?

Accepted Answer

Squareroot of (ơm squared+ ơp squared)

Answer

Total Process Variation (σt) is expressed as the square root of the sum of the squares of its independent components, specifically Gage Variation (σm) and Part Variation (σp). This relationship, often represented as σt = √(σm² + σp²), assumes that the variation introduced by the measurement system (gage) and the actual variation in the parts being measured are independent sources of variability within the process.

Question 2

In terms of Repeatability(?r) and Reproducibility(?o) variation, what is Gage Variation(?m)?

Accepted Answer

(ơr squared+ ơo squared)1/2

Answer

Gage Variation (σm), which represents the variability introduced by the measurement system, is calculated as the square root of the sum of the squares of Repeatability (σr) and Reproducibility (σo) variations. Repeatability refers to the variation when the same operator measures the same part multiple times, while Reproducibility refers to the variation between different operators measuring the same part. This root sum of squares formula combines these independent sources of measurement error.

Question 3

What GRR percentage must be exceeded before the gage needs to be replaced?

Accepted Answer

0.3

Answer

A GRR (Gage Repeatability and Reproducibility) percentage of 30% or more indicates that the measurement system is unacceptable. This threshold signifies that the measurement error is too large relative to the process variation, making the data unreliable for decision-making. Such a system needs significant improvement, repair, or replacement to ensure accurate measurements.

Question 4

What guidelines should you follow while choosing a sample?

Accepted Answer

Determine sample size using a formula and base it on the tolerance and confidence interval expected and standard deviation or the current error rate of the population

Answer

Choosing a sample size is a critical statistical decision, not an arbitrary one. It must be determined using appropriate formulas that consider factors like the desired confidence level, the acceptable margin of error (tolerance), and the variability (standard deviation) or proportion of defects in the population. This rigorous approach ensures the sample is representative and provides statistically valid insights for process improvement.

Question 5

Who is the process expert who rates the samples as acceptable, unacceptable, defective, etc.?

Accepted Answer

Master Appraiser

Answer

In a measurement system analysis or appraisal process, the Master Appraiser is the recognized expert. This individual possesses deep knowledge of the process and the measurement criteria, making them responsible for setting the standard and accurately rating samples. Their role is crucial for ensuring consistency and validity in the appraisal system, as they are the ultimate authority on sample classification.

Lean Six Sigma Black Belt Certification Practice Test

Lean Six Sigma Black Belt Certification Practice Test

FREE Lean Six Sigma Black Belt Certification Prep Questions and Answers