Lean Six Sigma Black Belt Certification Measure Phase: Data Analysis 3

Question 1

A Gauge R&R study reveals that %Gauge R&R is 28%. How should this measurement system be classified?

Accepted Answer

Marginal—acceptable depending on application and customer approval

Answer

A %Gauge R&R between 10% and 30% is considered marginal; it may be acceptable depending on the importance of the application and cost of repair.

Question 2

What is the relationship between Type I error (alpha) and Type II error (beta) when sample size is fixed?

Accepted Answer

Reducing alpha increases beta (they have an inverse relationship)

Answer

With a fixed sample size, decreasing alpha (the risk of a false positive) increases beta (the risk of a false negative) because the decision boundary shifts.

Question 3

In a Box-Cox transformation, what is the goal?

Accepted Answer

To stabilize variance and make non-normal data approximately normal

Answer

The Box-Cox transformation applies a power function to non-normal data to stabilize variance and achieve approximate normality for parametric analysis.

Question 4

Which statistic is used to assess the overall adequacy of a multiple regression model?

Accepted Answer

Adjusted R-squared

Answer

Adjusted R-squared measures the proportion of variance explained by the model while penalizing for adding unnecessary predictors, making it suitable for comparing models.

Question 5

A process produces 340 defects per million opportunities (DPMO). What sigma level does this correspond to approximately?

Accepted Answer

5 sigma

Answer

A DPMO of approximately 233 corresponds to 5 sigma; 340 DPMO is very close to the 5-sigma level using the 1.5-sigma shift convention.

Lean Six Sigma Black Belt Certification Practice Test

Lean Six Sigma Black Belt Certification Practice Test

Lean Six Sigma Black Belt Certification Measure Phase: Data Analysis 3