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Unformatted text preview: 3. D evelop a CUSUM chart for the thickness data of Example 21.2 of the SEM textbook using =0 and H =4 x . If the grand mean of the available data is used as the target T , how many chart violations occur? Repeat for an EWMA chart and a value of =0.25. 3. In a manufacturing process, the impurity level of the product is measured on a daily basis. When the process is operating normally, the impurity level is approximately normally distributed with a mean value of 0.800 % and a standard deviation of 0.021 %. The laboratory measurements for a period of eight consecutive days are shown below. From an SPC perspective, is there strong evidence to believe that the mean value of the impurity has shifted? Justify your answer. Day Impurity (%) 1 0.812 2 0.791 3 0.841 4 0.814 5 0.799 6 0.833 7 0.815 8 0.807 2...
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