Lean Six Sigma Black Belt Certification Measure Phase: Data Analysis 4

Question 1

A Black Belt uses Minitab to run a one-way ANOVA and obtains a p-value of 0.032. With alpha = 0.05, what is the correct conclusion?

Accepted Answer

Reject H0; at least one group mean differs significantly from the others

Answer

Since p = 0.032 < alpha = 0.05, we reject the null hypothesis and conclude that at least one group mean is significantly different.

Question 2

What does the concept of 'rational subgrouping' mean in the context of control charts?

Accepted Answer

Grouping samples so that special causes appear between subgroups rather than within them

Answer

Rational subgrouping organizes data so within-subgroup variation reflects only common causes, maximizing the chance that special causes manifest as between-subgroup differences.

Question 3

Which non-parametric test is the equivalent of the paired t-test when normality cannot be assumed?

Accepted Answer

Wilcoxon signed-rank test

Answer

The Wilcoxon signed-rank test is the non-parametric alternative to the paired t-test, comparing medians of two related samples when normality is violated.

Question 4

In a scatter diagram, a correlation coefficient (r) of -0.92 indicates:

Accepted Answer

A strong negative linear relationship

Answer

A correlation coefficient of -0.92 indicates a strong negative linear relationship, meaning as one variable increases, the other decreases substantially.

Question 5

A process engineer finds that the Pp is 1.6 but the Ppk is 0.9. What does this imply?

Accepted Answer

The process spread is adequate but the process is significantly off-center

Answer

A high Pp with a low Ppk indicates the process has sufficient inherent capability (spread) but is poorly centered relative to the specification limits.

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 4