In a semiconductor manufacturing company samples of 200 wafe

In a semiconductor manufacturing company, samples of 200 wafers are tested for defectives in the lot. The number of defectives n 20 such samples is shown in the following table. Set up a P chart for the process and estimate the standard deviation of the process. The following represent the number of solder defects observed oo 24 samples of five printed circuit boards: 7,6,8,10, 24,6, 5,4, 8,11.15, 8,4,16.11,12.8.6. S, 9, 7.14.8. 21. Using all the data, construct a U control chart and estimate the standard deviation of the process.

Solution