Significance testing dummy factors

The value of an effect and its standard deviation are calculated in the same way as for factorial designs. Multiply the responses by their contrast coefficients for a given factor, sum them, and divide this number by half the number of experiments (2n, for 4n experiments) to give the value of the effect. With no high-order interactions available in the design, either an independent estimate of repeatability or the use of dummy variables is essential. For m dummy variables, the effect standard deviation is calculated using equation 3.14, where ) is the measured effect of the Jth dummy factor. The significance of the effect is then determined by a Student s t test described earlier. 

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