Design of Experiments (DOE) Flashcards
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Read the first 7 Design of Experiments (DOE) flashcards as text
Which of the following is TRUE about replication in a DOE?
Answer: Replication involves completely re-running the entire experimental setup for a treatment combination
True replication means independently setting up and running an experimental condition again, which provides an estimate of pure experimental error and increases power.
A Yates algorithm in factorial DOE analysis is used to:
Answer: Systematically calculate effect estimates from experimental data
The Yates algorithm is a systematic computational method for calculating all main effects and interaction effects from a 2^k factorial experiment.
In a split-plot design, what distinguishes the 'whole-plot' factor from the 'sub-plot' factor?
Answer: Whole-plot factors are harder or more expensive to change between runs
Whole-plot factors are those that are difficult or costly to change (e.g., oven temperature requiring long reset times), so their levels are held fixed across multiple sub-plot factor combinations.
What does the coefficient of determination (R²) indicate in a DOE regression model?
Answer: The proportion of total variation in the response explained by the model
R² represents the fraction of response variation accounted for by the fitted model; a value close to 1 indicates the model explains most of the observed variation.
When a DOE residual plot shows a 'funnel' pattern (increasing spread with fitted values), this indicates:
Answer: Non-constant variance (heteroscedasticity) in the residuals
A funnel-shaped residual plot indicates non-constant variance, suggesting a data transformation (e.g., log or square root) may be needed.
In Taguchi's parameter design, 'inner array' factors are:
Answer: Control factors that the engineer can set and control
The inner array contains the control factors (those the engineer can set), while the outer array contains noise factors that represent uncontrollable variation in actual use.
Which of the following best describes the defining relation of a fractional factorial design?
Answer: The set of effects that equal the identity (I) and determine the alias structure
The defining relation is the set of generator words (each equal to I) from which all aliases can be derived by multiplying elements of the defining relation together.