Project Management lCHAPTER 13
TRUE/FALSE
13.1 PERT and CPM are quantitative analysis tools designed to schedule and control large projects.
13.2 PERT is a deterministic analysis tool allowing for precise times of activities within a project.
13.3 PERT had its beginnings in a military department of the United States.
13.4 CPM is a probabilistic analysis of managing a project.
13.5 An event is a point in time that marks the beginning or ending of an activity.
13.6 A network is a graphical display of a project that contains both activities and events.
13.7 The optimistic time is the greatest amount of time that could be required to complete an activity.
13.8 PERT is a network technique similar to CPM, but PERT allows for project crashing.
13.9 The most likely completion time of an activity is used to represent that activity’s time within a project.
13.10 The expected completion time and variance of an activity is approximated by the normal distribution in a PERT analysis.
13.11 PERT was developed for a project for which activity or task times were uncertain.
13.12 CPM was developed for use in managing projects which are repeated and about which we have good information as to activity or task completion times.
13.13 With PERT, we are able to calculate the probability of finishing the project on a particular day.
13.14 With CPM, we are able to calculate the probability of finishing the project on a particular day.
13.15 A PERT or CPM network shows activities and activity sequences.
13.16 One of the most difficult aspects of using PERT is defining the activities so that they have measurable/observable starts and finishes.
13.17 Before drawing a PERT or CPM network, we must identify each activity and their predecessors.
13.18 The three time estimates employed in PERT are: optimistic time, average time, and pessimistic time.
13.19 In the PERT process, if an activity has zero variance it must be on the critical path.
13.20 Given the variability of the activity completion time, the original critical path we identify in our PERT analysis may not always be the actual critical path as the project takes place.
13.21 In PERT, the activity completion times are modeled using the beta distribution.
13.22 In PERT, the earliest finish time in one activity will always be the earliest start time of the following activity.
13.23 In PERT, the earliest start time for an activity is equal to the latest of the earliest finish times of all of its immediate predecessors.
13.24 One of the limiting assumptions of PERT is that for any activity to start, all of its immediate predecessors must be complete.
13.25 One of the limiting assumptions of PERT is that all activities must be completed at some time during the project.
13.26 One of the most significant benefits of PERT is that it forces the project manager to sit down and plan the project in great detail – and thus come to an understanding of relationships between the activities.
13.27 Slack is the time an activity can be delayed without impacting the completion time of the project.
13.28 It is never possible to delay an activity without impacting the project completion time.
13.29 The variance of the project completion time is equal to the sum of the variances of all the activities.
13.30 In PERT, we assume that the project completion time can be modeled by the normal distribution.
13.31 One PERT/COST assumption is that money is spent at a constant rate over the time taken to complete an activity.
13.32 PERT helps the project manager understand both which activities must take place and which funds must be expended.
13.33 A limitation of PERT/COST is the assumption that money is spent at a constant rate over the time taken to complete the project.
13.34 In CPM, we assume that the cost to complete the task is a linear function of the time to complete the task.
13.35 In CPM, crashing an activity which is not on the critical path increases the cost of the project.
13.36 In CPM, if we are going to crash an activity, we should crash it to the maximum extent possible.
*13.37 In CPM, crashing an activity which is not on the critical path reduces the cost of the project just as much as crashing one on the critical path.
*13.38 One of the drawbacks to using either CPM or PERT to manage an actual project is the amount of data that must be collected over the life of the project to implement either method.
*13.39 In PERT, the variance in completion time is equal to the variance of the most time consuming activity on the critical path.
*13.40 Given the assumptions in PERT, the probability that a project will be completed in less time than required by the activities on the critical path is approximately 50%.
*13.41 One should always wait until an activity’s latest start time before commencing the activity.
*13.42 Using PERT/COST, one is able to complete the project for less money than using PERT alone.
*13.43 If an activity has 4 days of slack, and we delay it 2 days, the project will also be delayed two days.
*13.44 Gantt and PERT charts provide the same information, just in different formats.
*13.45 Gantt charts contain information as to the time taken by each activity, but not the sequential dependencies of the activities.
*13.46 Using PERT/COST as a management tool, it is always possible to bring a project in under budget.
MULTIPLE CHOICE
13.47 The critical path of a network is the
(a) shortest time path through the network.
(b) path with the fewest activities.
(c) path with the most activities.
(d) longest time path through the network.
(e) none of the above
13.48 In a PERT network, the earliest (activity) start time is the
(a) earliest time that an activity can be finished without delaying the entire project.
(b) latest time that an activity can be started without delaying the entire project.
(c) earliest time that an activity can start without violation of precedence requirements.
(d) latest time that an activity can be finished without delaying the entire project.
(e) none of the above
13.49 Slack time in a network is the
(a) time consuming job or task that is a key subpart of the total project.
(b) shortest amount of time that could be required to complete the activity.
(c) amount of time that you would expect it would take to complete the activity.
(d) amount of time that an activity can be delayed without delaying the entire project.
(e) none of the above
13.50 A network activity is a
(a) point in time that marks the beginning or ending of an activity.
(b) time consuming job that is a subpart of the total project.
(c) graphical display of a project.
(d) network technique that allows three time estimates for each activity in a project.
(e) the longest time path through the network.
13.51 Which of the following is not a concept associated with CPM?
(a) normal time
(b) probability
(c) normal cost
(d) crash cost
(e) deterministic network
13.52 PERT
(a) assumes we do not know ahead of time what activities must be completed.
(b) allows computation of the program’s evaluation.
(c) is a network technique that uses three time estimates for each activity in a project.
(d) is a deterministic network technique that allows for project crashing.
(e) none of the above
13.53 CPM
(a) assumes we do not know ahead of time what activities must be completed.
(b) is opposite to that of PERT, as it does not consider the network activities.
(c) is a network technique that allows three time estimates for each activity in a project.
(d) is a deterministic network technique that allows for project crashing.
(e) none of the above
13.54 Managers use the network analysis of PERT and CPM to help them
(a) derive flexibility by identifying noncritical activities.
(b) replan, reschedule, and reallocate resources such as manpower and finances.
(c) plan, schedule, monitor, and control large and complex projects.
(d) all of the above
13.55 In contrast to PERT or PERT/cost, CPM
(a) is a deterministic network model.
(b) uses crash times and costs.
(c) allows for calculating the least additional cost for shortening the project time.
(d) assumes that the activity times and costs are known with certainty.
(e) all of the above
13.56 The expected time in PERT is
(a) a weighted average of the most optimistic time, most pessimistic time, and four times the most likely time.
(b) the modal time of a beta distribution.
(c) a simple average of the most optimistic, most likely, and most pessimistic times.
(d) the square root of the sum of the variances of the activities on the critical path.
(e) none of the above
13.57 Given the following activity’s optimistic, most likely, and pessimistic time estimates of 4, 5, and 12 days, respectively, compute the PERT time for this activity.
(a) 5
(b) 6
(c) 7
(d) 12
(e) none of the above
13.58 Given the following activity’s optimistic, most likely, and pessimistic time estimates of 3, 3, and 9 days, respectively, compute the PERT time for this activity.
(a) 3
(b) 4
(c) 5
(d) 9
(e) none of the above
13.59 Given the following activity’s optimistic, most likely, and pessimistic time estimates of 4, 8, and 18 days, respectively, compute the PERT time for this activity.
(a) 4
(b) 8
(c) 9
(d) 18
(e) none of the above
13.60 Given the following activity’s optimistic, most likely, and pessimistic time estimates of 2, 10, and 20 days, respectively, compute the PERT variance for this activity.
(a) 3
(b) 6
(c) 9
(d) 18
(e) none of the above
13.61 Given the following activity’s optimistic, most likely, and pessimistic time estimates of 4, 12, and 18 days, respectively, compute the PERT variance for this activity.
(a) 2.33
(b) 5.44
(c) 8.00
(d) 64.00
(e) none of the above
13.62 Given an activity’s optimistic, most likely and pessimistic time estimates of 3, 5, and 15 days, respectively, compute the PERT standard deviation for this activity.
(a) 2
(b) 4
(c) 5
(d) 15
(e) none of the above
13.63 Given the following small project, the critical path is ______days.
Activity / ImmediatePredecessor / Time
(days)
A / - / 10
B / - / 4
C / A, B / 6
(a) 10
(b) 14
(c) 16
(d) 20
(e) none of the above
13.64 Given the following small project, the critical path is ______days.
Activity / ImmediatePredecessor / Time
(days)
A / - / 8
B / A / 4
C / - / 10
(a) 4
(b) 10
(c) 12
(d) 22
(e) none of the above
The following table provides information for questions 13.65 to 13.68.
The following represents a project with known activity times. All times are in weeks.
Activity / Immediate
Predecessor / Time
A / - / 4
B / - / 3
C / A / 2
D / B / 7
E / C, D / 4
F / B / 5
13.65 Using the data in Table 13-1, what is the minimum possible time required for completing the project?
(a) 8
(b) 14
(c) 25
(d) 10
(e) none of the above
13.66 Using the data in Table 13-1, what is the latest possible time that C may be started without delaying completion of the project?
(a) 0
(b) 4
(c) 8
(d) 10
(e) none of the above
13.67 According to Table 13-1, compute the slack time for activity D.
(a) 0
(b) 5
(c) 3
(d) 6
(e) none of the above
13.68 Using the data in Table 13-1, compute the latest finish time for activity E.
(a) 4
(b) 10
(c) 14
(d) 25
(e) none of the above
The following table provides information for questions 13.69 to 13.72.
Table 13-2The following represents a project with four activities. All times are in weeks.
Activity / Immediate
Predecessor / Optimistic
Time / Most
Likely
Time / Pessimistic
Time
A / - / 2 / 8 / 14
B / - / 8 / 8 / 8
C / A / 6 / 9 / 18
D / B / 5 / 11 / 17
13.69 According to the data in Table 13-2, what is the critical path?
(a) A, B
(b) A, C
(c) B, D
(d) A, B, C, D
(e) none of the above
13.70 According to the data in Table 13-2, what is the minimum expected completion time for the project?
(a) 18
(b) 19
(c) 37
(d) 11
(e) none of the above
13.71 According to Table 13-2, there are four activities in the project. Assume the normal distribution is appropriate to use to determine the probability of finishing by a particular time. If you wished to find the probability of finishing the project in 20 weeks or less, it would be necessary to find the variance and then the standard deviation to be used with the normal distribution. What variance would be used?
(a) 2
(b) 4
(c) 8
(d) 12
(e) none of the above
13.72 According to Table 13-2, there are four activities in the project. Assume the normal distribution is appropriate to use to determine the probability of finishing by a particular time. What is the probability that the project is finished in 16 weeks or less (round to two decimals)?
(a) 0.07
(b) 0.93
(c) 0.43
(d) 0.77
(e) none of the above
13.73 Consider a project that has an expected completion time of 60 weeks and a standard deviation of five weeks. What is the probability that the project is finished in 70 weeks or less (round to two decimals)?