Certified Six Sigma Black Belt Exam Certified Six Sigma Black Belt Design of Experiments (DOE) Questions and Answers 2

Question 1

In a 2^k factorial design, what does the term 'confounding' refer to?

Accepted Answer

Aliasing a higher-order interaction with a block effect

Answer

Confounding deliberately aliases a high-order interaction effect with the block effect so the experiment can be run in fewer blocks.

Question 2

A Six Sigma Black Belt runs a 2^4 full factorial with two replicates. How many total experimental runs are required?

Accepted Answer

32

Answer

A 2^4 design has 16 runs, and two replicates yield 16 × 2 = 32 total runs.

Question 3

Which of the following is the primary advantage of using a fractional factorial design over a full factorial?

Accepted Answer

It reduces the number of runs while still estimating main effects

Answer

Fractional factorials sacrifice information on higher-order interactions to significantly reduce the total number of experimental runs.

Question 4

What is the resolution of a 2^(5-2) fractional factorial design with generators I=ABCD and I=BCE?

Accepted Answer

Resolution III

Answer

The generators produce a word-length of three (BCE), making it a Resolution III design where main effects are aliased with two-factor interactions.

Question 5

In a Response Surface Methodology (RSM) study, what is the purpose of adding axial (star) points to a factorial design?

Accepted Answer

To allow estimation of quadratic (second-order) effects

Answer

Axial points extend the factorial design so that curved, second-order relationships between factors and the response can be modeled.

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