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

Question 1

A Black Belt is designing an experiment to optimize a chemical process with five factors.
Due to budget and time constraints, running a full factorial (2^5 = 32 runs) is not feasible.
The team needs to identify the most significant factors and two-factor interactions quickly.
Which of the following is the most appropriate initial approach?

Accepted Answer

A fractional factorial design to screen for the vital few factors and interactions with fewer runs.

Answer

A full factorial design to ensure all possible interactions are studied.

Answer

Response Surface Methodology (RSM) to find the optimal process settings.

Answer

A one-factor-at-a-time (OFAT) experiment to simplify the analysis.

Question 2

In a Design of Experiments (DOE), when the effect of one factor on the output response is dependent on the level of another factor, this phenomenon is known as:

Accepted Answer

An interaction effect

Answer

A main effect

Answer

Confounding

Answer

Replication

Question 3

A project team adds several center points to their 2-level factorial design. What is the primary reason for including these runs?

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 in the experiment.

Answer

To ensure the experiment is run in a random order.

Answer

To estimate the experimental error with fewer replicated runs.

Question 4

Which of the following describes a situation of 'confounding' in a fractional factorial experiment?

Accepted Answer

The effect of a main factor cannot be distinguished from the effect of a two-factor interaction.

Answer

The experiment produces a non-linear response surface.

Answer

The process output is influenced by uncontrollable 'noise' variables.

Answer

The measurement system variation is too high to trust the results.

Question 5

A Black Belt has completed a screening experiment and identified the two most critical factors influencing the process output. The next goal is to find the precise settings for these factors that will maximize the output. Which DOE technique is most appropriate for this optimization step?

Accepted Answer

Response Surface Methodology (RSM).

Answer

A new fractional factorial design with higher resolution.

Answer

A Taguchi design to minimize variation.

Answer

A full factorial design with only two levels.

Question 6

When analyzing the results of a two-level full factorial experiment, what does a large 'main effect' for a specific factor indicate?

Accepted Answer

Changing the factor from its low level to its high level causes a significant change in the average response.

Answer

The factor has a strong interaction with another factor.

Answer

The relationship between the factor and the response is non-linear.

Answer

The factor's effect is confounded with a block effect.