Question 1

Preceding activities are those that must occur before others can be done.

Accepted Answer

Preceding activities are those that are necessary prerequisites for other activities to occur. Without completing the preceding activities, the subsequent activities cannot be started or completed successfully. Therefore, the statement is true.

Question 2

An activity has an optimistic time estimate of 25 days,a most likely estimate of 29 days,and a pessimistic estimate of 34 days.What is the expected duration of the activity?

Accepted Answer

The expected duration of the activity can be calculated using the formula: (Optimistic + 4(Most Likely) + Pessimistic) / 6. Plugging in the values: (25 + 4(29) + 34) / 6 = 29.5 days, which is less than 31 days but greater than or equal to 29 days.

Question 3

The length of time expected to complete an activity assuming that its development proceeds normally is called the:

Accepted Answer

The "most likely duration" is the term used to describe the length of time expected to complete an activity assuming that its development proceeds normally, without any unforeseen delays or accelerations.

Question 4

An activity has an optimistic time estimate of 17 days,a most likely estimate of 22 days,and a pessimistic estimate of 32 days.What is the expected duration of the activity?

Accepted Answer

The expected duration of the activity can be calculated using the formula: (Optimistic + 4(Most Likely) + Pessimistic) / 6. Plugging in the values: (17 + 4(22) + 32) / 6 = 22.83 days.

Question 5

Project Test Bank is composed of activities we will refer to as A,B,C,and D for convenience (and lack of creativity).Durations and precedence requirements are shown in the table.Each of these activities can be conveniently laddered into two sub-activities of equal duration.The first half of each activity serves as the predecessor to its second half and the first half of the original following activity.What is the expected completion time of the laddered project? $$\begin{array} { | l | l | l | } 
\hline \text { Activity } & \text { Length } & \text { Predecessor } \
\hline \text { A } & 10 & -- \
\hline B & 18 & \text { A } \
\hline \mathrm { C } & 14 & \text { A } \
\hline \mathrm { D } & 20 & \text { B, C } \
\hline
\end{array}$$

Accepted Answer

The correct answer is A because the expected completion time of the laddered project is 34.

Question 6

At a merge point in a forward pass,the largest preceding early finish becomes the early start for that node.

Accepted Answer

This statement accurately describes the merging of multiple paths in a network diagram during forward pass calculation in project management techniques such as the Critical Path Method (CPM). At merge points, the earliest possible completion time (early finish) of all preceding activities/path(s) is determined, and this value is then assigned as the earliest start time for the merged activity/path. This helps identify the critical path - the longest sequence of activities with zero slack time, and hence the path that determines the overall project duration.

Question 7

Project Test Bank is composed of activities we will refer to as A,B,C,and D for convenience (and lack of creativity).Durations and precedence requirements are shown in the table.Each of these activities can be conveniently laddered into two sub-activities of equal duration.The first half of each activity serves as the predecessor to its second half and the first half of the original following activity.What is the expected completion time of the laddered project? $$\begin{array} { | l | l | l | } 
\hline \text { Activity } & \text { Length } & \text { Predecessor } \
\hline \text { A } & 10 & -- \
\hline B & 18 & \text { A } \
\hline C & 14 & \text { A } \
\hline D & 20 & \text { B, C } \
\hline
\end{array}$$

Accepted Answer

Laddering the project means breaking down each activity into two parts, each with half the original duration. The original project has activities A, B, C, and D with durations of 10, 18, 14, and 20 days, respectively. By laddering, we get:- A1 and A2 (5 days each),- B1 and B2 (9 days each),- C1 and C2 (7 days each),- D1 and D2 (10 days each).The critical path considering laddering and the precedence requirements (A before B and C; B and C before D) would be A1-A2-B1-B2-D1-D2. The total duration is 5 (A1) + 5 (A2) + 9 (B1) + 9 (B2) + 10 (D1) + 10 (D2) = 48 days. However, because B and C can start simultaneously after A, and their second halves (B2 and C2) can overlap with the first half of D (D1), the actual critical path duration is reduced. The longest path is through B (A1-A2-B1-B2-D1-D2), which totals 5 (A1) + 5 (A2) + 9 (B1) + 9 (B2) + 10 (D1) + 10 (D2) = 48, but with laddering and overlapping, the completion time is actually the sum of the longest sequence without unnecessary waiting, which is A (10) + B (18) + D (20) = 48. However, considering the correct calculation for the laddered and overlapped activities, the actual completion time is shorter. The correct calculation should consider the overlapping of activities and the correct sequence, leading to a different total duration. The mistake in the explanation is not accounting for the effective overlap in the laddered approach, which actually shortens the project duration from the original calculation. The correct approach would calculate the effective project duration based on the laddered activities and their overlaps, leading to a shorter duration than the longest individual path calculated without considering the laddering benefits. The correct answer, considering the laddering and the overlaps, should reflect the shortest project duration achievable with this method.

Question 8

The variance of an activity is given by:

Accepted Answer

The variance of an activity in PERT (Program Evaluation and Review Technique) is calculated using the formula [(b-a)/6]², where 'b' is the pessimistic time and 'a' is the optimistic time. The given option A is equivalent to this formula.

Question 9

An activity has a pessimistic time that is four times as long as its most likely time and six times as long as its optimistic time.If the activity variance is 12,what is the expected time?

Accepted Answer

The expected time is the average of the optimistic, most likely, and pessimistic times. The variance is the square of the standard deviation, which is the square root of the variance of the optimistic, most likely, and pessimistic times. The variance of the optimistic, most likely, and pessimistic times is 12, so the standard deviation is the square root of 12, which is 3.46. The expected time is the average of the optimistic, most likely, and pessimistic times, which is (3 + 6 + 18) / 3 = 9 days.

Question 10

Activity Z has estimates a = 5,b = 12,m = 7;activity X has estimates a = 5,b = 11,m = 6;and activity Y has estimates a = 3,b = 11,m = 8.Which of the following statements is BEST?

Accepted Answer

Activity Z has the lowest estimated time (7), followed by Activity X (6) and Activity Y (8). Therefore, Activity Z is the shortest and Activity Y is the longest. We cannot determine the standard deviation or variance from the given information.

Question 11

What does a network diagram illustrate and why are they important in project management?

Accepted Answer

The answer of What does a network diagram illustrate and...

Question 12

An activity has an optimistic time estimate of 17 days,a most likely estimate of 23 days,and a pessimistic estimate of 37 days.What is the variance of the activity?

Accepted Answer

The variance of an activity is given by the formula:Variance = (Pessimistic Estimate - Optimistic Estimate)^2 / 6Plugging in the given values, we get:Variance = (37 - 17)^2 / 6 = 20^2 / 6 = 400 / 6 = 66.66Therefore, the variance of the activity is 66.66 days, which is closest to option D) 11.11 days.

Question 13

Prior to creating a network,it is important to:

Accepted Answer

Understanding the activity precedence is crucial in creating a network because it determines the sequence in which activities should be performed. This allows for the creation of a logical and efficient network. While identifying loops and calculating float are also important in network creation, they come after understanding the activity precedence. Identifying the parties responsible for each activity is important, but is not crucial in network creation.

Question 14

An activity has an optimistic time estimate of 12 days,a most likely estimate of 16 days,and a pessimistic estimate of 22 days.What is the expected standard deviation of the activity?

Accepted Answer

The standard deviation for an activity in PERT is calculated as (Pessimistic - Optimistic) / 6. Here, it is (22 - 12) / 6 = 10 / 6 = 1.67 days, which falls between 1 and 2 days.

Question 15

What are hammock activities and when should they be used?

Accepted Answer

The answer of What are hammock activities and when should...

Question 16

Consider a project composed of activities X and Y having equal length and performed in that order.Both activities can be laddered such that the first half of each activity is the predecessor for its own second half,so X1 precedes X2 and Y1 precedes Y2.The first half of X1 is also the predecessor for Y1.If the laddering procedure were performed again activities X and Y would be divided in four parts each,with precedence working as it did in the first split.Derive an expression for the minimum length of the project as laddering increases.

Accepted Answer

The answer of Consider a project composed of activities X...

Question 17

Ray's shipment of materials hit every red light and traffic jam on the way to the site.Upon arrival,half of the material was judged defective,necessitating a trip back to the supplier,and then the same arduous journey back to the site once the new materials were loaded.Traffic was a little better on the second round but the flat tire and subsequent repair caused as much if not more delay than the first trip.In the final analysis:

Accepted Answer

The answer of Ray's shipment of materials hit every red...

Question 18

Burst activities are those with two or more successor activities.

Accepted Answer

Burst activities are those with two or more successor activities, but the term specifically used to describe this in project management is not "burst activities" but rather "split activities" or nodes where the path diverges into two or more paths. Burst activities might be confused with the term, but it's not a standard term for this concept.

Question 19

A merge activity has two or more immediate predecessors.

Accepted Answer

A merge activity is a point in a project where two or more paths converge, meaning that it has two or more immediate predecessors leading up to it.

Question 20

At a burst point in a backward pass,the largest succeeding late start becomes the late finish for that node.

Accepted Answer

The answer of At a burst point in a backward...

Quiz 9: Project Scheduling: Networks, Duration Estimation, and Critical Path