Lean Six Sigma Black Belt Certification FREE Lean Six Sigma Black Belt Improve Phase: DOE Questions and Answers 2 — Questions and Answers
Question 1: In a 2^3 full factorial design, how many experimental runs are required without replication?
- 6
- 8 (Correct answer)
- 9
- 12
Correct answer: 8
A 2^k design requires 2^3 = 8 runs for three factors each at two levels.
Question 2: What is the primary purpose of randomization in a designed experiment?
- To reduce the number of runs needed
- To minimize the effect of uncontrolled variables (Correct answer)
- To eliminate the need for replication
- To simplify the analysis of results
Correct answer: To minimize the effect of uncontrolled variables
Randomization helps ensure that uncontrolled nuisance variables are evenly distributed across experimental conditions, reducing bias.
Question 3: Which term describes the combined effect of two factors that cannot be explained by either factor alone?
- Confounding
- Interaction effect (Correct answer)
- Blocking effect
- Main effect
Correct answer: Interaction effect
An interaction effect occurs when the impact of one factor depends on the level of another factor.
Question 4: In a fractional factorial design, what is the consequence of using a lower resolution (e.g., Resolution III)?
- All interactions can be estimated independently
- Main effects are confounded with two-factor interactions (Correct answer)
- The experiment requires more runs than a full factorial
- Blocking is no longer possible
Correct answer: Main effects are confounded with two-factor interactions
Resolution III designs confound main effects with two-factor interactions, making it impossible to distinguish between them.
Question 5: What does the term 'center point' refer to in a DOE context?
- The median value of the response variable
- A run conducted at the midpoint of all factor levels (Correct answer)
- The average of all experimental results
- The optimal factor setting identified by the experiment
Correct answer: A run conducted at the midpoint of all factor levels
Center points are runs at the midpoint of each factor range, used to detect curvature in the response surface.
Question 6: A Black Belt wants to screen seven factors efficiently. Which design is most appropriate?
- Full factorial 2^7
- Plackett-Burman design (Correct answer)
- Central composite design
- Box-Behnken design
Correct answer: Plackett-Burman design
Plackett-Burman designs are saturated screening designs ideal for identifying the vital few factors from many candidates.
Lean Six Sigma Black Belt Certification FREE Lean Six Sigma Black Belt Improve Phase: DOE Questions and Answers 2
In a 2^3 full factorial design, how many experimental runs are required without replication?