Certified Six Sigma Black Belt Exam Design of Experiments (DOE) 4

Question 1

Which of the following is TRUE about replication in a DOE?

Accepted Answer

Replication involves completely re-running the entire experimental setup for a treatment combination

Answer

True replication means independently setting up and running an experimental condition again, which provides an estimate of pure experimental error and increases power.

Question 2

A Yates algorithm in factorial DOE analysis is used to:

Accepted Answer

Systematically calculate effect estimates from experimental data

Answer

The Yates algorithm is a systematic computational method for calculating all main effects and interaction effects from a 2^k factorial experiment.

Question 3

In a split-plot design, what distinguishes the 'whole-plot' factor from the 'sub-plot' factor?

Accepted Answer

Whole-plot factors are harder or more expensive to change between runs

Answer

Whole-plot factors are those that are difficult or costly to change (e.g., oven temperature requiring long reset times), so their levels are held fixed across multiple sub-plot factor combinations.

Question 4

What does the coefficient of determination (R²) indicate in a DOE regression model?

Accepted Answer

The proportion of total variation in the response explained by the model

Answer

R² represents the fraction of response variation accounted for by the fitted model; a value close to 1 indicates the model explains most of the observed variation.

Question 5

When a DOE residual plot shows a 'funnel' pattern (increasing spread with fitted values), this indicates:

Accepted Answer

Non-constant variance (heteroscedasticity) in the residuals

Answer

A funnel-shaped residual plot indicates non-constant variance, suggesting a data transformation (e.g., log or square root) may be needed.

Certified Six Sigma Black Belt Exam Practice Test

Certified Six Sigma Black Belt Exam Practice Test

Certified Six Sigma Black Belt Exam Design of Experiments (DOE) 4