Answer: b The free float or slack is the amount of time that an activity can be delayed before it affects the schedule of any other activity.. The free float or slack is the amount of ti
Trang 1Answers to the following questions can be found in chapter 2, ‘‘Time Manage-ment,’’ unless otherwise noted
1 Answer: b
Note that activities in a calendar schedule start on the beginning of the time period that they start on and end at the end of the time period that they finish
on A two-day activity starts on May 5 and ends on May 6, ES and EF
2 Answer: b
The free float or slack is the amount of time that an activity can be delayed before it affects the schedule of any other activity Activity F has free float but activity D does not Both have seven days of float, total float, or plain old float When calculating schedules and float with leads and lags, it is best to look at the next activity with no lead or lag and, after determining the dates, change them by the amount of the lead or lag
The free float or slack is the amount of time that an activity can be delayed before it affects the schedule of any other activity Activity F has free float but activity D does not Both have seven days of float, total float, or plain old float
Critical path is the list of activities that have zero total float It is dangerous to find the path that has the longest sum of the durations Path A B D F H has a duration of eight days but has a sum of the durations of ten days
The late start for activity F is May 12 It has a late start that is calculated to be two days before the late finish of activity D With leads and lags it is best to calculate the LS of the dependent activity, then the LF of the independent activity, and then adjust the LF of the independent activity to consider the FS lead
325
Trang 2The first work of the project is done on May 1, and the last work of the project
is finished on May 20
There is a lead of two days associated with the finish-start relationship between activities D and F If the relationship were a normal FS relationship, the ES of activity F would be May 7 A two day lead means it will start two days earlier,
or May 5
Since activity F has seven days of float it can be delayed for as much as seven days before it has any effect on the project completion
The early finish date of activity A is the same as its start date and the start of the project Activities start on the beginning of the time period that work begins and end on the end of the time period that work finishes This activity takes one day beginning in the morning of May 1 and finishing in the afternoon of May 1
10 Answer: c
The figure is called a precedence diagram It is recognizable because boxes are used to indicate the activities The arrows in a precedence diagram indicate the logical relationship between the activities The information about the activity
is inside or around the box An activity on arrow diagram will use circles to indicate events and the activity information will be put on the arrows The Gantt chart has no logic shown normally (now available on some project man-agement software) The length of the Gantt bar is proportional to a time scale showing the duration of the activity Although this diagram is also a network diagram, there are many other network diagrams in the world Precedence dia-gram is a much better answer
11 Answer: a
The finish-finish relationship in a precedence diagram says that the independent activity must finish before the dependent activity is permitted to finish In the schedule, if the turkey took five hours to roast and the sweet potatoes took one
The following table refers to questions 12 through 15
Trang 3o p ml EV SD CP EV CP SD CP VAR
H 9 13 10 10.33333 0.666667 10.33333 0.666667 0.444444
Total 32.33333 Total 0.944444
Prob 66% sd 1 33.30516 31.36151 Prob 95% sd 2 34.27698 30.38968 Prob 99% sd 3 35.24881 29.41786
12 Answer: c
The expected value of the project is the expected value of each of the tasks that are on the critical path, A C E H I The approximate expected value is the sum
of each of these task’s optimistic, pessimistic, and four times the most likely estimate divided by 6 When calculating the length of time that the project takes, it is important that you remember to only include the critical path activi-ties Other activities in the schedule are done in parallel with the critical path activities
13 Answer: b
devia-tions of the total standard deviation of the critical path items To total the standard deviation, first square the value for each critical path item’s standard deviation, add them up, and take the square root of the total
14 Answer: b
The expected value for activity B is the sum of the optimistic, pessimistic, and four times the most likely value, all divided by 6
15 Answer: c
The standard deviation for activity B is the difference between the optimistic estimate and the pessimistic estimate divided by 6
16 Answer: d
Trang 4Fast tracking a schedule is finding activities that can be done in parallel that were originally scheduled to be done in sequence
17 Answer: a
Crashing a schedule is improving the project completion date by any means that is economical and feasible In crashing a schedule an effort is made to find the largest schedule reduction for the least additional cost
18 Answer: d
The baseline schedule as well as the baseline budget and the baseline scope are the original project plans plus or minus any approved changes There are many other terms used to describe schedules, but the definition given is the definition
of the baseline schedule and therefore the best answer
19 Answer: b
Bar charts, also called Gantt charts, show activity start and end dates as well as expected durations, but do not usually show dependencies They are relatively easy to read and are frequently used in management presentations In a Gantt chart there is a horizontal time scale Activities are represented as bars above the time scale in such a way that the length of the bar is proportional to the elapsed time of the activity The start of the activity is on the left side of the bar and is above the date that it starts The right hand side of the bar is located over the finish of the activity
20 Answer: c
The critical path activities are those activities that have zero float There are exceptions When activities are forced to be done on specific dates (date con-straints), it is possible to create negative float When the project is resource constrained the critical path may change due to resource constraints
21 Answer: c
Resource leveling is a tool in most project management software and can also
be done manually In resource leveling an attempt is made to reduce overutiliza-tion of resources to their normal utilizaoverutiliza-tion
22 Answer: b
At the end of two weeks this task is 75% complete The PV was to be 4 person-weeks, two people working full time for two weeks The EV is therefore 3
Trang 523 Answer: b
Although total float is assigned to each of the tasks in the sequence, the total float can be used by any of them and it can only be used one time by any of them If the tasks are A B C D E and each has one day of float, if A is delayed
by one day, the total float at B C D E reduces to zero
24 Answer: c
Monte Carlo analysis is a simulation technique that assigns durations to tasks
in a schedule and then calculates the schedule information It repeats this as-signment and calculation many times and then reports statistical results, includ-ing the percent of time a task is on the critical path
25 Answer: a
Precedence diagramming method (PDM) This is a method of constructing a project network diagram using nodes to represent the activities and connecting them with arrows that show the dependencies This technique is also called activity-on-node (AON) and is the method used by nearly all project manage-ment software packages
Arrow diagramming method (ADM) This is a method of constructing a proj-ect network diagram using arrows to represent the activities and connproj-ecting them at nodes to show the dependencies This technique is also called activity-on-arrow (AOA) and, although less prevalent than PDM, is still the technique
of choice in some application areas
26 Answer: d
The project schedule includes at least planned start and expected finish dates for each detail activity A schedule update is any modification to the schedule information which is used to manage the project Float is the amount of time that an activity may be delayed from its start without delaying the project finish date Although the project’s budget is the time phased expenditure of the proj-ect funds, it is not the projproj-ect schedule and therefore the best answer
27 Answer: d
Mandatory dependencies are those which are inherent in the nature of the work being done Discretionary dependencies are those which are defined by the project management team They should be used with care (and fully docu-mented) since they may limit later scheduling options
Resource requirements The resources assigned to them will significantly influ-ence the duration of most activities and the project itself
Trang 6Resource capabilities The duration of most activities will be significantly in-fluenced by the capabilities of the humans and material resources assigned to them
28 Answer: a
Critical path method (CPM) calculates a single, deterministic early and late start and finish date for each activity based on specified, sequential network logic and a single duration estimate Program evaluation and review technique (PERT) uses sequential network logic and a weighted average duration estimate
to calculate project duration Although there are surface differences, PERT dif-fers from CPM primarily in that it uses the distribution’s mean (expected value) instead of the most likely estimate originally used in CPM and associates the standard deviation of the estimate to allow the range of values and a probability
of occurrence to be calculated for the project
29 Answer: b
The activity that has eighteen days of free float can be rescheduled without having to reschedule any other activity in the project If this activity is resched-uled to start two weeks later, the resource will not be overutilized, and the project will remain on schedule
30 Answer: a
The person who is working on the task that has free float of five days can be used on the task that is in trouble for five days without affecting the other task schedules in the project The person working on the task that has total float of eight days can be used on the task that is in trouble, but since there is zero free float for this task, there will have to be a rescheduling of other tasks to allow this
31 Answer: c
The logical analysis of the schedule often produces a preliminary schedule that requires more resources during certain time periods than are available, or re-quires changes in resource levels that are not manageable Heuristics such as
‘‘allocate scarce resources to critical path activities first’’ can be applied to de-velop a schedule that reflects such constraints Resource leveling, because of the limited availability of the resources, often results in a project duration that is longer than the preliminary schedule
32 Answer: b
The Guide to the PMBOK defines the lowest level of the work breakdown
Trang 7struc-ture as the work package It goes on to say that the work package is a unit of work that can be assigned to a person or organization It also says that the work package can be broken down into tasks, and that tasks can be broken down into activities
33 Answer: c
When a risk is identified, budget and schedule time are identified and put into the contingency reserve If the risk actually occurs the money is used from the contingency reserve and added to the operating budget of the project The total project budget contains the operating project budget or baseline, contingency reserve, and the management reserve The project budget baseline is increased
by the amount of the risk although the total project budget stays the same The schedule baseline is changed to reflect the new activities that have to be done
34 Answer: d
The Guide to the PMBOK gives the following as inputs to the activity definition:
• Work breakdown structure
• Scope statement
• Historical information
• Constraints
• Assumptions
35 Answer: c
Fast tracking a project means that project tasks and activities are rescheduled from being done in sequence to being done in parallel Crashing a project means doing anything practical that can be done to reduce the schedule Fast tracking only involves doing things in parallel that would have otherwise been done in sequence
36 Answer: b
The CPM or critical path method is used to determine the activities that have zero float or close to zero float These activities should be managed more care-fully than other activities in the schedule since other activities not on the critical path will have free float and total float that allows their schedules to be more flexible
37 Answer: c
PERT stands for program evaluation and review technique In PERT each of the activities has the optimistic, pessimistic, and most likely duration estimated
Trang 8332 Preparing for the Project Management Professional Certification Exam
A weighted average is then taken to estimate the expected value of the activity The weighted average is calculated by adding the optimistic, pessimistic, and four times the most likely duration and dividing by 6 The standard deviation
of the activity can also be calculated by subtracting the optimistic duration from the pessimistic duration and dividing by 6
38 Answer: d
In the PERT calculation the standard deviation is calculated by squaring the standard deviation for each of the activities on the critical path of the project, adding them together, and then taking the square root This is the standard deviation of the project Plus or minus two standard deviations from the ex-pected value of the project duration will have a range of values such that the project has a 95% probability of actually finishing within the dates calculated
39 Answer: a PERT is a probabilistic method used to determine the estimated project com-pletion based on the statistical estimating of the project durations CPM is a deterministic method using specific values for activity and task durations
40 Answer: c
The Guide to the PMBOK defines the lowest level of the work breakdown
struc-ture as the work package It goes on to say that the work package is a unit of work that can be assigned to a person or organization The work package can
be broken down into tasks, and tasks can be broken down into activities.TE AM