服务管理：运作、战略与信息技术(原书第9版)试卷MGH_9thIM_First_Exam_Solution.docVIP

First Exam PAGE 356 351 FIRST EXAM SOLUTION 1. The project network diagram below shows activities with expected times in days. a. Note on the network all scheduling times ES, LS, EF, LF, and slack time TS for each activity. (10 pts.) A B C D E F G H I ES 0 0 0 4 4 4 10 9 15 EF 4 3 4 10 7 9 14 15 17 LS 1 6 0 5 12 4 11 9 15 LF 5 9 4 11 15 9 15 15 17 TS 1 6 0 1 8 0 1 0 0 b. For the network above, assume an activitys daily expedite cost in dollars per day is equal to the activitys time (e.g., the cost to reduce the activity time of H by one day is $6.) Further, assume that each activity can be crashed only one day. What activities should be crashed to reduce the project duration by 3 days at least cost? (10 pts.) Project Duration Activity Crashed Cost 17 Normal - 16 I 2 15 C 4 14 F and A or G 9 Assume that the activities A, D, G, and I are on the critical path. Further, assume that the variance of each activity is equal to its expected time. How many days would you expect the project to take with a 90 percent assurance of completion? Recall that a standard normal deviation of 1.28 provides 10 percent in one tail of the distribution. (5 pts.) Z = 1.28 = (X-16)/(4+6+4+2)? X = 1.28 (4) + 16 = 21.12 ≈ 21 days 2. A health clinic is being planned to serve a rural area in west Texas. The service area contains four communities A, B, C, D with populations in (000s) of 2, 1, 3, and 2, respectively. The (x, y) coordinate location of each community is given below: A: (6, 2) B: (8, 6) C: (5, 9) D: (3, 4) a. Using the populations in (000s) as weights, what is the median value? (2 pts.) Median = (1+2+2+3)/2 = 4 b. Use the grid below to recommend a cross median location for the health clinic minimizing total weighted metropolitan distance traveled. (13 pts.) Cross Median Location on line (x,y): 5,4 – 5,6 3. The IRS office reviews tax filings for errors and has compiled the following sample from five days of 1040 filings each containing 20 documents: 4, 2, 1,