Certified Six Sigma Black Belt Exam General 2

Question 1

In the DMAIC cycle, which phase focuses on identifying root causes of defects using data analysis tools?

Accepted Answer

Analyze

Answer

The Analyze phase uses statistical tools like fishbone diagrams and hypothesis testing to identify and verify root causes.

Question 2

Which Six Sigma metric represents the number of defects per million opportunities (DPMO) at a Six Sigma quality level?

Accepted Answer

3.4

Answer

A true Six Sigma process produces no more than 3.4 DPMO, accounting for a 1.5 sigma long-term shift.

Question 3

A Black Belt is conducting a hypothesis test and sets alpha (α) = 0.05. What does this significance level represent?

Accepted Answer

The acceptable probability of rejecting a true null hypothesis

Answer

Alpha is the significance level representing the probability of committing a Type I error — rejecting a true null hypothesis.

Question 4

Which tool is most appropriate for prioritizing potential failure modes by their Risk Priority Number (RPN)?

Accepted Answer

FMEA

Answer

Failure Mode and Effects Analysis (FMEA) calculates RPN by multiplying Severity, Occurrence, and Detection ratings to prioritize risks.

Question 5

What is the primary purpose of a Box-Cox transformation in Six Sigma analysis?

Accepted Answer

To normalize non-normal data before parametric testing

Answer

The Box-Cox transformation applies a power function to non-normal data to make it approximately normal, enabling valid parametric analysis.

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