FREE Lean Six Sigma Black Belt Improve Phase: DOE Questions and Answers

Question 1

A Six Sigma team is planning a Design of Experiments (DOE) to understand a complex process with 7 factors.
The team has limited time and resources, so a full factorial experiment is not feasible.
They need to identify the most influential factors (main effects) for further investigation.
Which type of experimental design is most appropriate for this initial stage?

Accepted Answer

A screening design, such as a fractional factorial

Answer

Response Surface Methodology (RSM)

Answer

A full factorial design with fewer factors

Answer

One-Factor-at-a-Time (OFAT) experimentation

Question 2

In a fractional factorial Design of Experiments, the term 'resolution' is used to describe the degree of confounding. What is the primary characteristic of a Resolution III design?

Accepted Answer

Main effects are confounded with two-factor interactions.

Answer

Main effects are confounded with other main effects.

Answer

No main effects are confounded with two-factor interactions.

Answer

Two-factor interactions are confounded with other two-factor interactions.

Question 3

A Black Belt is setting up a DOE and decides to include several runs where all factors are set at their midpoint level. What is the primary purpose of adding these 'center points' to the experiment?

Accepted Answer

To check for curvature in the relationship between factors and the response.

Answer

To increase the number of factors that can be studied.

Answer

To reduce the total number of experimental runs required.

Answer

To allow the experiment to be run over multiple days.

Question 4

During the execution of a designed experiment, an unexpected machine calibration issue occurred halfway through the runs. To account for this known source of variation, which is not one of the primary factors being studied, the experimenter should use which technique?

Accepted Answer

Blocking

Answer

Replication

Answer

Randomization

Answer

Confounding

Question 5

Which of the following is a primary advantage of using a full factorial DOE compared to a fractional factorial DOE?

Accepted Answer

It allows for the estimation of all main effects and all interaction effects, free from confounding.

Answer

It requires fewer resources and experimental runs.

Answer

It is the most effective design for screening a large number of factors.

Answer

It can only be used to study linear relationships between variables.

Question 6

A project team is conducting a DOE to optimize the yield of a chemical process. They have identified three critical factors. Their goal is to not only understand the main effects and interactions but also to model potential curvature in the response to find the precise optimal settings. Which experimental design approach is most suitable?

Accepted Answer

Response Surface Methodology (RSM)

Answer

A Resolution III fractional factorial design

Answer

A Plackett-Burman screening design

Answer

A Taguchi L4 array