In a semiconductor manufacturing company, samples of 200 wafers are tested for defectives in the lot. See the number of defectives in 20 such samples in the following table.

(a) Set up a P chart for this process. Is the process in statistical control?

(b) Suppose that instead of samples of size 200, we have samples of size 100. Use the data to set up a P chart for this process. Revise the control limits if necessary.

(c) Compare the control limits in parts (a) and (b). Explain why they differ.

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No. of No. of Sample Defectives Sample Defectives 1 44 11 52 63 12 74 3 40 13 43 4. 35 14 50 29 15 60 56 16 38 40 17 36 38 18 65 9. 74 19 41 10 66 20 95