![EBK PRINCIPLES OF OPERATIONS MANAGEMENT](https://www.bartleby.com/isbn_cover_images/8220102744059/8220102744059_largeCoverImage.jpg)
Concept explainers
The estimated times and immediate predecessors for the activities in a project at George Kyparis’s retinal scanning company are given in the following table. Assume that the activity times are independent.
a) Calculate the expected time and variance for each activity.
b) What is the expected completion time of the critical path? What is the expected completion time of the other path in the network?
c) What is the variance of the critical path? What is the variance of the other path in the network?
d) If the time to complete path A–C is
e) If the time to complete path B–D is normally distributed, what is the probability that this path will be finished in 22 weeks or less?
f) Explain why the probability that the critical path will be finished in 22 weeks or less is not necessarily the probability that the project will be finished in 22 weeks or less.
![Check Mark](/static/check-mark.png)
Want to see the full answer?
Check out a sample textbook solution![Blurred answer](/static/blurred-answer.jpg)
Chapter 3 Solutions
EBK PRINCIPLES OF OPERATIONS MANAGEMENT
- Dave Fletcher was able to determine the activity times for constructing his laser scanning machine. Fletcher would like to determine ES, EF, LS, LF, and slack for each activity. The total project completion time and the critical path should also be determined. Here are the activity times: Activity Time (weeks) Immediate Predecessor(s) Activity Time (weeks) Immediate Predecessor(s)A 7 - E 4 BB 8 - F 7 BC 4 A G 11 C, ED 1 A H 6 D , F Dave's earliest start (ES) and earliest finish (EF) are: Activity ES EF A 0 7 B 0 8 C 7 11 D 7 88 E 8 12 Part 7 F ? ? G ? ? H ? ?arrow_forwardDave Fletcher was able to determine the activity times for constructing his laser scanning machine. Fletcher would like to determine ES, EF, LS, LF, and slack for each activity. The total project completion time and the critical path should also be determined. Here are the activity times: Activity Time (weeks) Immediate Predecessor(s) Activity Time (weeks) Immediate Predecessor(s) A 7 − E 5 B B 8 − F 6 B C 4 A G 11 C, E D 3 A H 7 D , F Part 2 Dave's earliest start (ES) and earliest finish (EF) are: Part 3 Part 4 Part 5 Part 6 Part 7 Part 8 Part 9 Part 10 Dave's latest start (LS) and latest finish (LF) are:…arrow_forwardDave Fletcher was able to determine the activity times for constructing his laser scanning machine. Fletcher would like to determine ES, EF, LS, LF, and slack for each activity. The total project completion time and the critical path should also be determined. Here are the activity times: Activity Time (weeks) Immediate Predecessor(s) Activity Time (weeks) Immediate Predecessor(s) A 7 − E 4 B B 6 − F 5 B C 4 A G 10 C, E D 2 A H 8 D , F Part 2 Dave's earliest start (ES) and earliest finish (EF) are: Part 3 Part 4 Part 5 Part 6 Part 7 Part 8 Part 9 Part 10 Dave's latest start (LS) and latest finish (LF) are:…arrow_forward
- Dave Fletcher was able to determine the activity times for constructing his laser scanning machine. Fletcher would like to determine ES, EF, LS, LF, and slack for each activity. The total project completion time and the critical path should also be determined. Here are the activity times: Dave's earliest start (ES) and earliest finish (EF) are: Activity Time (weeks) Immediate Predecessor(s) Activity Time (weeks) Immediate Predecessor(s) A B C D 7 2 A Activity A F G H ES | FF 5 6 9 7 B B C. E D, Farrow_forwardDave Fletcher was able to determine the activity times for constructing his laser scanning machine. Fletcher would like to determine ES, EF, LS, LF, and slack for each activity. The total project completion time and the critical path should also be determined. Here are the activity times: Activity Time (weeks) Immediate Predecessor(s) Activity Time (weeks) Immediate Predecessor(s) A B с D 7 8 80 31 3 A A Dave's earliest start (ES) and earliest finish (EF) are: Activity A EFI G H ES EF 7 4 5 11 6 B B C, E D, Farrow_forwardDave Fletcher was able to determine the activity times for constructing his laser scanning machine. Fletcher would like to determine ES, EF, LS, LF, and slack for each activity. The total project completion time and the critical path should also be determined. Here are the activity times: Dave's earliest start (ES) and earliest finish (EF) are: Activity Time (weeks) Immediate Predecessor(s) Activity Time (weeks) Immediate Predecessor(s) A B C D 7 6 3 2 A A Activity A ES EFGH EF 7 3 6 11 6 B B C, E D, Farrow_forward
- Consider a project that has been modeled as in the table below. Part a) Draw the PERT/CPM network for this project and determine the project’s expected completion time μP and its critical path. Part b) Suppose the standard deviations of the activity durations are σA = 2, σB = 1, σC = 0, σD = 2, σE = 3, and σF = 0. Then please estimate the standard deviation of the overall project’s standard deviation σP . Part c) Suppose for the standard Normal random variable Z, we know P[−1 ≤ Z ≤ +1] ' 68%, P[−2 ≤ Z ≤ +2] ' 95%, and P[−3 ≤ Z ≤ +3] ' 99.7%. Then, approximately what time T is one for which there is only a less than 2.5% chance for the completion time to beat (be shorter than)? *Please answer a-c and type your work and answers or write them neatly please* Thank youarrow_forwardConsider a project that has been modeled as in the table below. Part a) Draw the PERT/CPM network for this project and determine the project’s expected completion time μP and its critical path. Part b) Suppose the standard deviations of the activity durations are σA = 2, σB = 1, σC = 0, σD = 2, σE = 3, and σF = 0. Then please estimate the standard deviation of the overall project’s standard deviation σP . Part c) Suppose for the standard Normal random variable Z, we know P[−1 ≤ Z ≤ +1] ' 68%, P[−2 ≤ Z ≤ +2] ' 95%, and P[−3 ≤ Z ≤ +3] ' 99.7%. Then, approximately what time T is one for which there is only a less than 2.5% chance for the completion time to beat (be shorter than)? *Please answer a-c and either type your work and answers or write them neatly showing each step, please* NO EXCEL Thank you!arrow_forwardSuppose that the project team has arrived at the following time estimates for activity B (Select site and survey) of the St. John’s Hospital project: a = 7 weeks, m = 8 weeks, and b = 15 weeks a. Calculate the expected time and variance for activity B. b. Calculate the expected time and variance for the other activities in the project.arrow_forward
- Consider the project described in the table below: Activity Duration A B C D E F G H 9 4 8 8 5 7 4 6 OEST-9 and LCT = 15 OEST=9 and LCT = 13 Immediate Predecessor What is the earliest start time (EST) and latest completion time (LCT) of activity B? OEST=9 and LCT = 20 OEST-9 and LCT-17 - A A A B B,C C,D E,F,Garrow_forwardDave Fletcher was able to determine the activity times for constructing his laser scanning machine. Fletcher would like to determine ES, EF, LS, LF, and slack for each activity. The total project completion time and the critical path should also be determined. Here are the activity times: Activity A B C D Time (weeks) 7 6 2 2 Dave's earliest start (ES) and earliest finish (EF) are: Time Immediate Predecessor(s) Activity (weeks) E 4 6 10 6 A A Activity A B ES 0 0 F G H EF 7 Immediate Predecessor(s) B B C, E D, Farrow_forwardA project network is shown below, with three time estimates (Optimistic Time-Most Likely Time-Pessimistic Time (in days)) for each activity in the network. a. Compute the expected time for each activity in the project network. b. Identify and list all possible paths in the project network. Compute the expected duration for each path in the project network. c. Identify the critical path(s) in the project network. What is the expected project completion time? d. Compute the variance of each activity on the critical path(s). e. Determine the project variance and project standard deviation. Use the PERT analysis results in 2(c) and 2(e) to answer questions (f), (g), (h), and (i) below:f. What is the probability that the project can be completed within 22 days of its start? g. What is the probability that the project can be completed within 16 days of its start? h. Determine the project deadline that gives this project a 78% chance of on-time completion. i. Determine the project deadline…arrow_forward
- Practical Management ScienceOperations ManagementISBN:9781337406659Author:WINSTON, Wayne L.Publisher:Cengage,Operations ManagementOperations ManagementISBN:9781259667473Author:William J StevensonPublisher:McGraw-Hill EducationOperations and Supply Chain Management (Mcgraw-hi...Operations ManagementISBN:9781259666100Author:F. Robert Jacobs, Richard B ChasePublisher:McGraw-Hill Education
- Purchasing and Supply Chain ManagementOperations ManagementISBN:9781285869681Author:Robert M. Monczka, Robert B. Handfield, Larry C. Giunipero, James L. PattersonPublisher:Cengage LearningProduction and Operations Analysis, Seventh Editi...Operations ManagementISBN:9781478623069Author:Steven Nahmias, Tava Lennon OlsenPublisher:Waveland Press, Inc.
![Text book image](https://www.bartleby.com/isbn_cover_images/9781337406659/9781337406659_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781259667473/9781259667473_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781259666100/9781259666100_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9780135198100/9780135198100_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781285869681/9781285869681_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781478623069/9781478623069_smallCoverImage.gif)