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 his 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. a. The manager noticed that the longest time took to service a car was 25.94 minutes. Suppose the distribution of times to service a car was normal, with a mean of 15. Use your knowledge of a normal distribution to let the manager know what the standard deviation is for the time 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? OA. OB OC. OD. 16 12- 16- 12- 167 12- 16 12-1 8- thu 8- ant Anth Am 10 20 10 Construct a control chart for the mean. Which graph below shows an X-chart for the data? B. O c. O 20- 20 estach a warha c. Based on these data, what would you conclude about the service process? O A. Since two points on the x-chart are below the lower control limit, 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. OC. Since eight consecutive points are decreasing on the x-chart, the process is out of control. OD. Since two points on the R-chart are above the upper controllimit, the process is out of control. d. Based on your findings on the R-chart, would it be advisable to draw conclusions based on the x-chart? O 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. O B. Since the x-chart and the R-chart are not related, use the x-chart to draw conclusions. OC. 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. OD. Since the R-chart indicates that the process is under control, use the x-chart to draw conclusions. Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 15.33 12.72 14.00 17.55 11.47 13.78 12.54 14.44 15.63 15.05 15.12 20.38 13.76 16.65 14.90 13.84 17.26 16.36 12.21 12.79 2 18.30 18.36 13.29 14.69 25.94 16.59 16.48 16.28 15.19 14.35 13.04 14.13 15.48 12.65 12.24 12.04 16.45 13.16 15.08 17.16 Employee 3 13.54 12.89 11.20 13.31 13.10 19.38 13.42 15.00 13.08 15.45 13.88 14.39 19.17 15.18 16.29 15.70 11.35 14.93 16.14 15.12 4 11.67 15.44 16.83 14.44 16.14 6.58 16.68 16.72 15.38 18.60 16.58 15.56 20.31 12.59 13.96 18.36 13.21 16.96 15.15 16.65 5 11.66 12.50 24.42 15.92 21.06 17.22 17.85 16.13 15.02 14.07 12.46 13.32 16.62 16.16 16.54 11.35 15.06 12.45 12.40 13.73 20 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 his 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. a. The manager noticed that the longest time took to service a car was 25.94 minutes. Suppose the distribution of times to service a car was normal, with a mean of 15. Use your knowledge of a normal distribution to let the manager know what the standard deviation is for the time 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? OA. OB OC. OD. 16 12- 16- 12- 167 12- 16 12-1 8- thu 8- ant Anth Am 10 20 10 Construct a control chart for the mean. Which graph below shows an X-chart for the data? B. O c. O 20- 20 estach a warha c. Based on these data, what would you conclude about the service process? O A. Since two points on the x-chart are below the lower control limit, 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. OC. Since eight consecutive points are decreasing on the x-chart, the process is out of control. OD. Since two points on the R-chart are above the upper controllimit, the process is out of control. d. Based on your findings on the R-chart, would it be advisable to draw conclusions based on the x-chart? O 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. O B. Since the x-chart and the R-chart are not related, use the x-chart to draw conclusions. OC. 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. OD. Since the R-chart indicates that the process is under control, use the x-chart to draw conclusions. Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 15.33 12.72 14.00 17.55 11.47 13.78 12.54 14.44 15.63 15.05 15.12 20.38 13.76 16.65 14.90 13.84 17.26 16.36 12.21 12.79 2 18.30 18.36 13.29 14.69 25.94 16.59 16.48 16.28 15.19 14.35 13.04 14.13 15.48 12.65 12.24 12.04 16.45 13.16 15.08 17.16 Employee 3 13.54 12.89 11.20 13.31 13.10 19.38 13.42 15.00 13.08 15.45 13.88 14.39 19.17 15.18 16.29 15.70 11.35 14.93 16.14 15.12 4 11.67 15.44 16.83 14.44 16.14 6.58 16.68 16.72 15.38 18.60 16.58 15.56 20.31 12.59 13.96 18.36 13.21 16.96 15.15 16.65 5 11.66 12.50 24.42 15.92 21.06 17.22 17.85 16.13 15.02 14.07 12.46 13.32 16.62 16.16 16.54 11.35 15.06 12.45 12.40 13.73 20