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Factorial designs involve testing several (n) factors at two levels, high and low. A Fractional Factorial experiment uses only a half (2n-1), a quarter (2n-2), or some other division by a power of two of the number of treatments that would be required for a Full Factorial Experiment.
A Full Factorial design with 3 factors (23 design) would require 8 treatments. The example shows a 23-1 design, it requires only 4 treatments:
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Treatment
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A
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B
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C
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1
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-1
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-1
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+1
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2
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+1
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-1
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-1
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3
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-1
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+1
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-1
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4
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+1
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+1
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+1
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The Fractional Factorial design is created by aliasing Factor C with the Interaction AB. This is a Resolution III design.
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