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Three-Level Factorial Designs¶
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A full factorial with three levels on every factor, so the design has 3^k runs for k factors.
What this design gives you¶
Three settings on a factor is enough to estimate a quadratic term for it, so this design can hold curvature for every factor at once without axial points. It is a full factorial, so nothing is aliased. The model it builds stops at 7-way interactions, though: higher-order interactions are never created, so with eight or more factors the design has degrees of freedom the model does not use.
The cost is the run count, which is 3 to the power of the number of factors: 9 runs for two factors, 27 for three, 81 for four, 243 for five.
Every control¶
Every control on every page this builder shows for this design is on Options.
See Also¶
- N-Level Factorial Design, when the factors need different numbers of levels
- Two Level Factorial Designs
- Central Composite Design, curvature at a lower run count
- Categorical Inputs