Certified Six Sigma Black Belt Exam Certified Six Sigma Black Belt Practice 1

Question 1

A Black Belt wants to assess the relationship between a continuous input variable and a continuous output variable. Which statistical method is most appropriate for quantifying this relationship?

Accepted Answer

Simple linear regression

Answer

Simple linear regression models the relationship between a continuous predictor (X) and a continuous response (Y), producing an equation that quantifies the direction, strength, and predictive power of that relationship — exactly what is needed here.

Question 2

In the Control phase, a process shows a sudden shift in the mean on an X-bar chart. Which out-of-control rule most directly detects this type of shift?

Accepted Answer

One point beyond the 3-sigma control limit

Answer

A single point beyond the 3-sigma control limit (Western Electric Rule 1) is the primary signal for detecting a sudden, large shift in process mean. The other rules detect gradual drifts or unusual clustering rather than abrupt shifts.

Question 3

A Six Sigma team calculates a process Cp of 1.5 but a Cpk of 0.8. What does this discrepancy most likely indicate?

Accepted Answer

The process is significantly off-center relative to the specification limits

Answer

Cp measures potential capability (spread only), while Cpk accounts for both spread and centering. A high Cp with a low Cpk indicates the process has adequate inherent spread but is shifted away from the target, meaning centering is the primary problem.

Question 4

During the Improve phase, a team runs a 2^3 full factorial experiment and discovers a significant two-factor interaction between factors A and B. What is the best next step?

Accepted Answer

Set factor A at the level that makes the B effect most favorable, then optimize B

Answer

When a significant interaction exists, factors cannot be optimized independently. The correct approach is to examine the interaction plot and choose the level of one factor (A) that maximizes the favorable effect of the other (B), then optimize within that context.

Question 5

A Black Belt is selecting a sampling plan to verify incoming material quality. The team wants to control the risk of accepting a bad lot (consumer's risk) at no more than 10%. Which parameter directly defines this risk?

Accepted Answer

Beta (β)

Answer

Beta (β) is the probability of a Type II error — failing to reject a bad lot, which is the consumer's risk. AQL defines the quality level associated with producer's risk, while LTPD defines the defect level at which the consumer's risk (beta) is specified.

Certified Six Sigma Black Belt Exam Practice Test

Certified Six Sigma Black Belt Exam Practice Test

Certified Six Sigma Black Belt Exam Certified Six Sigma Black Belt Practice 1