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

Question 1

A project team is conducting an experiment to optimize a chemical process.
To prevent unforeseen variables, such as changes in ambient temperature or raw material batch variations throughout the day, from systematically biasing the results, the team decides to run the experimental trials in a non-sequential, randomly generated order.
This practice is known as:

Accepted Answer

Randomization

Answer

Replication

Answer

Blocking

Answer

Confounding

Question 2

In a fractional factorial experiment, the design resolution describes the degree to which effects are aliased with one another. If an experiment has a Resolution IV design, what does this imply?

Accepted Answer

No main effects are aliased with any two-factor interactions, but two-factor interactions are aliased with each other.

Answer

Main effects are aliased with other main effects.

Answer

Main effects are aliased with two-factor interactions.

Answer

All main effects and two-factor interactions are aliased with three-factor interactions.

Question 3

A Black Belt is analyzing the results of a 2-level, 3-factor (A, B, C) full factorial experiment. When reviewing the interaction plot for factors A and B, the lines representing the low and high levels of factor B are not parallel and cross each other. What is the most appropriate interpretation of this plot?

Accepted Answer

There is likely a significant interaction between factors A and B.

Answer

There is a strong main effect for factor A, but not for factor B.

Answer

Neither factor A nor factor B has a significant effect on the response.

Answer

The experimental data contains a significant number of outliers.

Question 4

A research and development team needs to investigate the effects of 8 different factors on product yield. A full factorial experiment would require 2^8 = 256 runs, which is too expensive and time-consuming. The team's primary goal is to identify the few factors that have the most significant main effects, and they are willing to accept that some two-factor interactions might be confounded. Which type of experimental design is most suitable for this situation?

Accepted Answer

A fractional factorial screening design

Answer

Response Surface Methodology (RSM)

Answer

A full factorial design with blocking

Answer

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

Question 5

Which of the following describes a situation where the effect of one factor is indistinguishable from the effect of another factor or interaction?

Accepted Answer

Confounding

Answer

Replication

Answer

Collinearity

Answer

Interaction

Question 6

After using a fractional factorial experiment to identify the two most critical factors (Temperature and Pressure) affecting a product's strength, a process engineer now wants to determine the precise settings for these two factors that will maximize the strength. Which of the following is the most appropriate next step?

Accepted Answer

Use Response Surface Methodology (RSM) to model and optimize the response.

Answer

Conduct another screening experiment with more factors.

Answer

Perform a Gage R&R study on the strength measurement system.

Answer

Implement a control chart for Temperature and Pressure.