Consider Exercise 8-38. Determine the sensitivity of the control limits on the complication rate using values of 0.2% and 0.5%.

Exercise 8-38

A building contractor subcontracts to a local merchant a job involving hanging wallpaper. To have an idea of the quality level of the merchant’s work, the contractor randomly selects 300 m² and counts the number of blemishes. The total number of blemishes for 30 samples is 80. Construct the centerline and control limits for an appropriate chart. Is it reasonable for the contractor to set a goal of an average of 0.5 blemishes per 100 m²?

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TABLE 8-33 Number Number of Items Number Number of Items Sample Restrained Not Checked Sample Restrained Not Checked 1 100 4 14 40 3 2 50 3 15 80 2 3 80 8 16 80 4 4 60 4 17 120 6 5 120 14 18 100 8 100 8 19 120 10 80 4 20 80 5 8 100 21 60 8 60 2 22 100 4 10 80 12 23 100 100 120 11 7 24 80 4 12 25 120 5 13 60 15