Q8 IM13DFinal
This is file Q8IM13D - The fourth of five files for solutions to this chapter.
23. The sample means and standard deviations gathered in a calibration project by the Weighrite Corporation were observed for sample sizes of 10, as show in worksheet Prob. 13-23. Construct - and s-charts and discuss the results.
Answer
23. See data and control charts below and spreadsheet Prob.13-23XSWeigh.xls for details. For the Weighrite Corporation, the center line, CL: = 8.659; CLs : = 7.474 a. Control limits for the - s charts are:
± A3 = 8.659 ± 0.975 (7.474) = 1.372 to 15.946
For the s-chart: UCLs = B4 = 1.716 (7.474) = 12.825 LCLs = B3 = 0
b. The process appears to be in statistical control, because values are distributed randomly about the mean, all values lie within control limits, and there are no unusual patterns on the or s-charts.
24. The temperature in a computer lab at Coyote University is very important for proper functioning of the computer equipment. The data in the worksheet Prob.13-24 shows the results of 30 samples of 5 each, taken at random at different times of day over a three month time period. Construct - and s charts and discuss the results.
Answer
24. See data and control charts below and spreadsheet Prob.13-24XSCoyote.xls for details. For the Coyote University computer lab, the center line, CL: = 72.071; CLs : = 1.159 a. Control limits for the - s charts are:
± A3 = 72.071 ± 1.43 (1.159) = 70.414 to 73.728
For the s-chart: UCLs = B4 = 2.09 (1.159) = 2.422 LCLs = B3 = 0
b. The process appears to be in statistical control, although there seems to be a tendency for values to hug the center lines on both the and s-charts. However, all values lie within control limits.
25. Calculate the process capability statistics for the outside diameters of the bottles made on the injection molding machine at the Moby Molding Co. (from Prob. 13-22). Use 0.12 as the upper tolerance limit and -0.10 as the lower
23. The sample means and standard deviations gathered in a calibration project by the Weighrite Corporation were observed for sample sizes of 10, as show in worksheet Prob. 13-23. Construct - and s-charts and discuss the results.
Answer
23. See data and control charts below and spreadsheet Prob.13-23XSWeigh.xls for details. For the Weighrite Corporation, the center line, CL: = 8.659; CLs : = 7.474 a. Control limits for the - s charts are:
± A3 = 8.659 ± 0.975 (7.474) = 1.372 to 15.946
For the s-chart: UCLs = B4 = 1.716 (7.474) = 12.825 LCLs = B3 = 0
b. The process appears to be in statistical control, because values are distributed randomly about the mean, all values lie within control limits, and there are no unusual patterns on the or s-charts.
24. The temperature in a computer lab at Coyote University is very important for proper functioning of the computer equipment. The data in the worksheet Prob.13-24 shows the results of 30 samples of 5 each, taken at random at different times of day over a three month time period. Construct - and s charts and discuss the results.
Answer
24. See data and control charts below and spreadsheet Prob.13-24XSCoyote.xls for details. For the Coyote University computer lab, the center line, CL: = 72.071; CLs : = 1.159 a. Control limits for the - s charts are:
± A3 = 72.071 ± 1.43 (1.159) = 70.414 to 73.728
For the s-chart: UCLs = B4 = 2.09 (1.159) = 2.422 LCLs = B3 = 0
b. The process appears to be in statistical control, although there seems to be a tendency for values to hug the center lines on both the and s-charts. However, all values lie within control limits.
25. Calculate the process capability statistics for the outside diameters of the bottles made on the injection molding machine at the Moby Molding Co. (from Prob. 13-22). Use 0.12 as the upper tolerance limit and -0.10 as the lower