The following partial Excel add-in (MegaStat) regression output for the service
ID: 3128587 • Letter: T
Question
The following partial Excel add-in (MegaStat) regression output for the service time data relates to predicting service times for 1, 2, 3, 4, 5, 6 and 7 copiers. Predicted values for: Minutes (y)
Report a point estimate of and a 95 percent confidence interval for the mean time to service four copiers. (Round your answers to 3 decimal places.)
Confidence interval = [ , ]
Report a point prediction of and a 95 percent prediction interval for the time to service four copiers on a single call. (Round your answers to 3 decimal places.)
Prediction interval = [ , ]
If we examine the service time data, we see that there was at least one call on which Accu-Copiers serviced each of 1, 2, 3, 4, 5, 6 and 7 copiers. The 95 percent confidence intervals for the mean service times on these calls might be used to schedule future service calls. To understand this, note that a person making service calls will (in, say, a year or more) make a very large number of service calls. Some of the person’s individual service times will be below, and some will be above, the corresponding mean service times. However, since the very large number of individual service times will average out to the mean service times, it seems fair to both the efficiency of the company and to the person making service calls to schedule service calls by using estimates of the mean service times. Therefore, suppose we wish to schedule a call to service five copiers. Examining the computer output, we see that a 95 percent confidence interval for the mean time to service five copiers is [130.121, 138.763]. Since the mean time might be 138.763 minutes, it would seem fair to allow 138 minutes to make the service call. Now suppose we wish to schedule a call to service four copiers. Determine how many minutes to allow for the service call. (Round your answer to the nearest whole number.)
Service call ________minutes
95% Confidence Intervals 95% Prediction Intervals Copiers (x) Predicted lower upper lower upper Leverage 1 34.155 27.004 41.306 20.082 48.228 .348 2 59.227 53.784 64.669 45.940 72.513 .202 3 84.298 80.170 88.427 71.494 97.103 .116 4 109.370 105.711 113.030 96.709 122.031 .091 5 134.442 130.121 138.763 121.574 147.310 .127 6 159.514 153.780 165.247 146.105 172.922 .224 7 184.586 177.102 192.069 170.341 198.830 .381 (a)Report a point estimate of and a 95 percent confidence interval for the mean time to service four copiers. (Round your answers to 3 decimal places.)
Point estimate = ______Confidence interval = [ , ]
b)Report a point prediction of and a 95 percent prediction interval for the time to service four copiers on a single call. (Round your answers to 3 decimal places.)
Point prediction = ______Prediction interval = [ , ]
(d)If we examine the service time data, we see that there was at least one call on which Accu-Copiers serviced each of 1, 2, 3, 4, 5, 6 and 7 copiers. The 95 percent confidence intervals for the mean service times on these calls might be used to schedule future service calls. To understand this, note that a person making service calls will (in, say, a year or more) make a very large number of service calls. Some of the person’s individual service times will be below, and some will be above, the corresponding mean service times. However, since the very large number of individual service times will average out to the mean service times, it seems fair to both the efficiency of the company and to the person making service calls to schedule service calls by using estimates of the mean service times. Therefore, suppose we wish to schedule a call to service five copiers. Examining the computer output, we see that a 95 percent confidence interval for the mean time to service five copiers is [130.121, 138.763]. Since the mean time might be 138.763 minutes, it would seem fair to allow 138 minutes to make the service call. Now suppose we wish to schedule a call to service four copiers. Determine how many minutes to allow for the service call. (Round your answer to the nearest whole number.)
Service call ________minutes
Explanation / Answer
Report a point estimate of and a 95 percent confidence interval for the mean time to service four copiers. (Round your answers to 3 decimal places.)
Point estimate = 109.370
Confidence interval = [ 105.711 , 113.030 ]
b)
Report a point prediction of and a 95 percent prediction interval for the time to service four copiers on a single call. (Round your answers to 3 decimal places.)
Point prediction = 109.370
Prediction interval = [ 96.709 , 122.031 ]
(d)
If we examine the service time data, we see that there was at least one call on which Accu-Copiers serviced each of 1, 2, 3, 4, 5, 6 and 7 copiers. The 95 percent confidence intervals for the mean service times on these calls might be used to schedule future service calls. To understand this, note that a person making service calls will (in, say, a year or more) make a very large number of service calls. Some of the person’s individual service times will be below, and some will be above, the corresponding mean service times. However, since the very large number of individual service times will average out to the mean service times, it seems fair to both the efficiency of the company and to the person making service calls to schedule service calls by using estimates of the mean service times. Therefore, suppose we wish to schedule a call to service five copiers. Examining the computer output, we see that a 95 percent confidence interval for the mean time to service five copiers is [130.121, 138.763]. Since the mean time might be 138.763 minutes, it would seem fair to allow 138 minutes to make the service call. Now suppose we wish to schedule a call to service four copiers. Determine how many minutes to allow for the service call. (Round your answer to the nearest whole number.)
95% CI for four copiers =(105.711,113.030)
minutes to allow for the Service call 113 minutes
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.