# In their book Empirical Model Building and Response Surfaces (John Wiley, 1987), G. E. P. Box and

## Question:

In their book *Empirical Model Building and Response Surfaces* (John Wiley, 1987), G. E. P. Box and N. R. Draper describe an experiment with three factors. The data shown in Table 8E.7 are a variation of the original experiment on p. 247 of their book. Suppose that these data were collected in a semiconductor manufacturing process.

a. The response is the average of three readings on resistivity for a single wafer. Fit a quadratic model to this response.

b. The response is the standard deviation of the three resistivity measurements. Fit a first-order model to this response.

c. Where would you recommend that we set if the objective is to hold mean resistivity at 500 and minimize the standard deviation?

## Step by Step Answer:

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## Managing Controlling and Improving Quality

**ISBN:** 978-0471697916

1st edition

**Authors:** Douglas C. Montgomery, Cheryl L. Jennings, Michele E. Pfund