Lean Six Sigma Black Belt Certification Lean Six Sigma Black Belt Certification 1

Question 1

In a full factorial Design of Experiments (DOE) with 4 factors each at 2 levels, how many experimental runs are required?

Accepted Answer

16

Answer

A full factorial DOE with k factors at 2 levels requires 2^k runs. With 4 factors: 2^4 = 16 runs. This ensures all combinations of factor levels are tested, allowing estimation of all main effects and interactions.

Question 2

A Gauge R&R study reports that the %Study Variation attributable to the measurement system is 28%. According to AIAG guidelines, how should this result be classified?

Accepted Answer

Marginal — may be acceptable depending on the application and cost of improvement

Answer

AIAG MSA guidelines classify measurement systems as: <10% = acceptable, 10–30% = marginal (acceptable based on importance of application and cost of the gauge), >30% = unacceptable. At 28%, the system is marginal and judgment is required before relying on it.

Question 3

What is the consequence of committing a Type II error (β error) in hypothesis testing during a DMAIC Analyze phase?

Accepted Answer

Failing to detect a real effect and concluding no significant relationship exists

Answer

A Type II (beta) error occurs when you fail to reject a false null hypothesis — you miss a real effect. In DMAIC, this means concluding an X variable has no significant impact when it actually does, causing the true root cause to be overlooked.

Question 4

In Value Stream Mapping, Process Cycle Efficiency (PCE) is calculated as:

Accepted Answer

Value-added time divided by total lead time

Answer

PCE = Value-Added Time / Total Lead Time. A PCE below 25% typically signals a significant lean improvement opportunity. It quantifies how much of the total time a product spends in the value stream actually transforms it into something the customer pays for.

Question 5

A Black Belt is monitoring the count of defects per unit on a line where the number of units inspected per shift varies. Which control chart is most appropriate?

Accepted Answer

u-chart

Answer

The u-chart tracks defects per unit when subgroup size varies. The c-chart also monitors defect counts but requires a constant subgroup size. The p-chart and np-chart track the proportion or number of defective units (pass/fail), not the count of individual defects.

Lean Six Sigma Black Belt Certification Practice Test

Lean Six Sigma Black Belt Certification Practice Test

Lean Six Sigma Black Belt Certification Lean Six Sigma Black Belt Certification 1