The stated goal of a chain of service stores is to provide a lube and oil change for anyone's automobile in 15 minutes. The manager at one store thinks that there is a growing disparity among her workers in the time it takes to lube and change the oil of an automobile. To monitor this, the manager has selected a sample of 20 days and has recorded the time it took five randomly selected employees to service an automobile. The data are found below. Complete parts a through d. Click the icon to view the data. The standard deviation is minutes. (Round to two decimal places as needed.) b. Use the data to construct an x- and an R-chart. Construct a control chart for the range. Which graph below shows Data - A. 24- 20 16- 12 8- 4- 0- 0 10 20 n O D. Employee Day 1 2 3 4 5 1 15.13 18.30 13.54 11.67 11.66 2 12.72 18.36 12.89 15.44 12.50 3 14.00 13.29 11.20 16.83 24.05 4 17.55 14.69 13.31 14.44 15.92 5 11.47 18.22 13.10 16.14 21.06 24- 20- 16- 12 8 4- 0- 0 10 20 6 13.78 16.59 25.74 4.46 17.22 12.54 Construct a control chart for the mean. Which graph below shows 16.48 13.42 16.68 17.85 8 14.44 16.28 15.00 16.72 16.13 9 15.63 15.19 13.08 15.38 15.02 A. D. 10 15.05 14.35 15.45 18.60 14.07 11 15.12 13.04 13.88 16.58 12.46 20- 20- 12 20.77 14.13 14.39 15.56 13.32 13 13.76 15.48 19.17 20.31 16.62 14 16.65 12.65 15.18 12.59 16.16 10- 0 10 20 15 14.90 12.32 16.29 13.96 16.54 10- 16 13.84 12.04 15.70 18.07 11.35 0 10 20 17 17.26 16.45 11.35 13.21 15.06 18 16.36 13.16 14.68 16.96 12.45 c. Based on these data, what would you conclude about the servi 19 12.21 15.08 16.14 15.15 12.40 20 12.79 17.16 15.12 16.65 13.87 A. Since ten points in a row are below the centerline on the B. Since all of the points on the R-chart and x-chart are betw C. Since one point on the x-chart is below the lower control li D. Since one point on the R-chart is above the upper control Print Done d. Based on your findings on the R-chart, would it be advisable to A. Since the x-chart uses R to determine the control limits and the R-chart indicates that the process is out of control, do not use the x-chart to draw conclusions. B. Since the R-chart indicates that the process is out of control, the x-chart will indicate that the process is out of control as well. C. Since the x-chart and the R-chart are not related, use the x-chart to draw conclusions. D. Since the R-chart indicates that the process is under control, use the x-chart to draw conclusions. The stated goal of a chain of service stores is to provide a lube and oil change for anyone's automobile in 15 minutes. The manager at one store thinks that there is a growing disparity among her workers in the time it takes to lube and change the oil of an automobile. To monitor this, the manager has selected a sample of 20 days and has recorded the time it took five randomly selected employees to service an automobile. The data are found below. Complete parts a through d. a. The manager noticed that the longest time it took to service a car was 25.74 minutes. Suppose the distribution of times to service a car was normal, with a mean of 15. Without analyzing the sample data, use your knowledge of a normal distribution to give the manager an estimate for the population standard deviation for the time it takes to service a car. The standard deviation is minutes. (Round to two decimal places as needed.) b. Use the data to construct an x- and an R-chart. Construct a control chart for the range. Which graph below shows an R-chart for the data? A. 24- 20- 16- 12 8- 4- 0- 0 10 20 B. 24- 201 16- 127 8- 4- 0+ 0 10 20 Construct a control chart for the mean. Which graph below shows an x-chart for the data? A. B. 20- 20- why @ 10- 0 10 20 10- 0 10 20 c. Based on these data, what would you conclude about the service process? A. Since ten points in a row are below the centerline on the R-chart, the process is out of control. B. Since all of the points on the R-chart and X-chart are between the control limits, the process is under control. O C. Since one point on the X-chart is below the lower control limit, the process is out of control. O D. Since one point on the R-chart is above the upper control limit, the process is out of control. 20 16- 12 20- D. 24- 20- 16 12- 8 h 0 10 20 0 10 20 D. 20- Mayta 10- 10- 0 10 20 0 10 20 d. Based on your findings on the R-chart, would it be advisable to draw conclusions based on the X-chart? A. Since the x-chart uses R to determine the control limits and the R-chart indicates that the process is out of control, do not use the x-chart to draw conclusions. B. Since the R-chart indicates that the process is out of control, the x-chart will indicate that the process is out of control as well. C. Since the x-chart and the R-chart are not related, use the x-chart to draw conclusions. D. Since the R-chart indicates that the process is under control, use the x-chart to draw conclusions.