hw2_new_new

# hw2_new_new - IEOR 130 Methods of Manufacturing Improvement...

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IEOR 130 Methods of Manufacturing Improvement Spring, 2009 Prof. Leachman Second homework assignment - due Thursday Feb. 19. 1. A control chart is being set up to track the resistivity after the ion implantation process step. Five sample measurements are made from one wafer per lot. The average of the measurements and the range of the measurements are computed. One hundred observations from 20 wafers have been collected. The average mean is 97.5, and the average range of the wafer measurements is 5.21. (a) Assuming the process was stable during processing of the 20 wafers, determine three-sigma control limits for R and X-bar charts. (b) Suppose the mean of the resistivity shifts to 100.0. What is the probability that the X-bar chart will make a Type 2 error in the next lot? (c) What is the probability the X-bar chart will make Type 2 errors in the next five lots? (A Type-2 error means the process is out of control but the control chart does not detect this.) 2. A process is monitored using an X-bar chart with UCL = 13.8 and LCL = 8.2. The process standard deviation is estimated to be 6.6. If the X-bar chart is based on three-sigma limits,

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hw2_new_new - IEOR 130 Methods of Manufacturing Improvement...

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