A. A textile manufacturer wants to set up a control chart for irregularities (.e.g. oil stains, shop soil, loose threads, and tears) per 100 square yards of carpet. The following data were collected from a sample of twenty 100-square-yard pieces of carpet

Sample # 1 2 3 4 5 6 7 8 9 10
Irregularities 11 8 9 12 4 16 5 8 17 10
Sample # 11 12 13 14 15 16 17 18 19 20
Irregularities 11 5 7 12 13 8 19 11 9 10

Using the above data, set up the appropriate control chart using 3-sigma limits and determine if the process is in control. Also plot the chart

B.Computer upgrades have a nominal time of 80 minutes. Samples of five observations each have been taken, and the results are as listed below. Using the factors A2, D3 and D4, determine upper and lower control limits for mean and range charts, and decide if the process is in control. Draw the X-bar chart and R-chart also in order to illustrate your conclusions

Sample #
1 2 3 4 5 6
79.2 80.5 79.6 78.9 80.5 79.7
78.8 78.7 79.6 79.4 79.6 80.6
80.0 81.0 80.4 79.7 80.4 80.5
78.4 80.4 80.3 79.4 80.8 80.0
81.0 80.1 80.8 80.6 78.8 81.1