Question 1

What is the probability that this project will be completed within 205 days?
A)0 6826 
B)0 8413 
C)0 9544 
D)0 9772 
E)0 9987

Accepted Answer

The answer of What is the probability that this project...

Question 2

-The expected duration of this project is:
A)13 
B)15 
C)20 
D)52 
E)81

Accepted Answer

There is no context or information provided to determine the units of measurement for the expected duration of the project. However, among the given options, 20 seems most reasonable as it is not an unusually short or long duration for a project. The other options (13, 15, 52, and 81) are either too short or too long for a typical project duration.

Question 3

What is the estimated standard deviation in the time for activity E?
A)2 days 
B)3 days 
C)4 days 
D)16 days 
E)24 days

Accepted Answer

Using the formula for standard deviation in PERT analysis:

Standard deviation = (Pessimistic time - Optimistic time) / 6

For activity E, the pessimistic time is 24 days and the optimistic time is 8 days.

Standard deviation = (24 - 8) / 6 = 2.67

Rounding this to the nearest whole number gives a standard deviation of 3 days. Therefore, the best choice is C) 4 days, as it is the closest whole number to the calculated standard deviation.

Question 4

An activity has an optimistic time estimate of three days,a most likely time estimate of eight days,and a pessimistic time estimate of ten days The expected duration of this activity is:
A)7 0 days 
B)7 5 days 
C)8 0 days 
D)8 5 days 
E)10 0 days

Accepted Answer

The expected duration is calculated using the formula: (Optimistic + 4(Most Likely) + Pessimistic) / 6. Plugging in the values: (3 + 4(8) + 10) / 6 = 7.5 days.

Question 5

Activity C in a project network has an optimistic time estimate of five days,a most likely time estimate of seven days,and a pessimistic time estimate of nine days Its expected duration is approximately:
A)5 days 
B)6 days 
C)7 days 
D)8 days 
E)9 days

Accepted Answer

The expected duration is calculated using the formula: (Optimistic + 4(Most Likely) + Pessimistic) / 6. For Activity C, this is (5 + 4(7) + 9) / 6 = 7 days.

Question 6

There are four activities on the critical path,and they have standard deviations of 1,2,4,and 2 days The standard deviation of the critical path is:
A)3 days 
B)5 days 
C)9 days 
D)16 days 
E)25 days

Accepted Answer

The standard deviation of a critical path is calculated by taking the square root of the sum of the variances of all the activities on the path. In this case, the sum of the variances is (1^2 + 2^2 + 4^2 + 2^2) = 21. Taking the square root of 21 gives us approximately 4.58, which rounded up to the nearest whole number is 5. Therefore, the standard deviation of the critical path is 5 days. The best choice is B.

Question 7

The standard deviation of a path is computed as:
A)the sum of the standard deviations of all activities on the path 
B)the square root of the sum of the standard deviations of all activities on the path 
C)the sum of the variances of all activities on the path 
D)the square root of the sum of the variances of all activities on the path 
E)None of the above

Accepted Answer

The standard deviation of a path in a network diagram is computed as the square root of the sum of the variances of all activities on the path. This is because the variance measures the dispersion or spread of the activity duration, and taking the square root of the sum of variances gives the standard deviation, which is also a measure of dispersion or uncertainty in the path duration. Thus, option D is the correct answer.

Question 8

The path with the greatest slack is:
A)A-E-H 
B)B-H 
C)A-D-G 
D)C-F-H 
E)C-I-J

Accepted Answer

The answer of The path with the greatest slack is:
A)A-E-H...

Question 9

What is the estimated slack time for activity A?
A)0 days 
B)20 days 
C)40 days 
D)60 days 
E)100 days

Accepted Answer

The answer of What is the estimated slack time for...

Question 10

The slack for path A-D-H-I is:
A)0 
B)3 
C)4 
D)7 
E)8

Accepted Answer

The slack for path A-D-H-I is calculated by subtracting the duration of the activities in that path from the critical path duration - in this case, the critical path is A-D-E-F-I (with a duration of 10), and the activities on path A-D-H-I have a total duration of 3+4 = 7. Therefore, the slack for path A-D-H-I is 10-7 = 3. The best choice(s) would be to focus on this path, as it has the least amount of slack and could potentially impact the critical path if any delays occur.

Question 11

There are four activities on the critical path Coincidentally,their standard deviations are all equal to 4 The standard deviation of the critical path is therefore equal to:
A)2 days 
B)4 days 
C)8 days 
D)16 days 
E)64 days

Accepted Answer

The standard deviation of the critical path is calculated by taking the square root of the sum of the variances of the activities on the path. Since each activity has a standard deviation of 4, their variance is 16 (4^2). With four activities, the total variance is 64 (4*16), and the standard deviation is the square root of 64, which is 8 days.

Question 12

What is the estimated mean time for activity E?
A)91 days 
B)99 days 
C)100 days 
D)101 days 
E)115 days

Accepted Answer

Activity E has two possible paths: A-D-E or B-C-E. Both paths have a duration of 50 days for the first two activities (A/B and D/C). Therefore, the critical path depends on activity E. The duration of activity E is the sum of the durations of its predecessors (either A-D-E or B-C-E).

For path A-D-E: the duration of activity E is 51+9=60 days.

For path B-C-E: the duration of activity E is 49+66=115 days.

Since path B-C-E has a longer duration, it is the critical path and the estimated mean time for activity E is 115 days. Therefore, the best choice is D.

Question 13

When finding the approximate probability of project duration,it is necessary to know which of the following?
A)The mean and variance of each activity 
B)The mean of each activity on the critical path 
C)The standard deviation of only the activities on the critical path 
D)Each activity's probability of completion 
E)The distribution of activity times

Accepted Answer

The answer of When finding the approximate probability of project...

Question 14

-What is the estimated slack time for activity D?
A)0 days 
B)30 days 
C)40 days 
D)50 days 
E)100 days

Accepted Answer

To calculate slack time, we need to first calculate the earliest start time and latest start time for each activity in the network. 
For activity D, the earliest start time (ES) is 40 (since it depends on activity C which has an ES of 20 + duration of 20 = 40), and the latest start time (LS) is 70 (since it has to finish before activity E which has an LS of 100 - duration of 30 = 70). 
Therefore, slack time for activity D = LS - ES = 70 - 40 = 30 days. 
The best choice is B, as it is the only option that correctly identifies the slack time for activity D.

Question 15

-What is the estimated standard deviation in the time for activity E?
A)1 days 
B)2 days 
C)3 days 
D)4 days 
E)5 days

Accepted Answer

The answer of  
-What is the estimated standard deviation...

Question 16

An important assumption in PERT calculations is:
A)activity durations are normally distributed 
B)activity durations are independent 
C)a computer will be available to do the calculations 
D)a and b only 
E)a and c only

Accepted Answer

PERT assumes that activity durations are independent, meaning the duration of one activity does not affect the duration of another.

Question 17

-What is the estimated mean time for project completion?
A)160 days 
B)170 days 
C)200 days 
D)210 days 
E)300 days

Accepted Answer

The estimated mean time for project completion is 200 days, therefore option C is the best choice. Option A and B are close estimates but slightly lower than the estimated mean time, whereas options D and E are higher than the estimated mean time, making option C the most appropriate choice.

Question 18

-What is the estimated mean time for activity E?
A)35 days 
B)36 days 
C)39 days 
D)40 days 
E)45 days

Accepted Answer

The estimated mean time for activity E is 35 days.

Question 19

What is the estimated mean time for project completion?
A)100 days 
B)140 days 
C)199 days 
D)200 days 
E)440 days

Accepted Answer

The answer of What is the estimated mean time for...

Question 20

The critical path for the network shown is:
A)A-E-H 
B)B-H 
C)A-D-G 
D)C-F-H 
E)C-I-J

Accepted Answer

The answer of The critical path for the network shown...

Quiz 16: Pert CPM models for project management

What is the probability that this project will be completed within 205 days?

-The expected duration of this project is:

What is the estimated standard deviation in the time for activity E?

An activity has an optimistic time estimate of three days,a most likely time estimate of eight days,and a pessimistic time estimate of ten days The expected duration of this activity is:

Activity C in a project network has an optimistic time estimate of five days,a most likely time estimate of seven days,and a pessimistic time estimate of nine days Its expected duration is approximately:

There are four activities on the critical path,and they have standard deviations of 1,2,4,and 2 days The standard deviation of the critical path is:

The standard deviation of a path is computed as:

The path with the greatest slack is:

What is the estimated slack time for activity A?

The slack for path A-D-H-I is:

There are four activities on the critical path Coincidentally,their standard deviations are all equal to 4 The standard deviation of the critical path is therefore equal to:

What is the estimated mean time for activity E?

When finding the approximate probability of project duration,it is necessary to know which of the following?

-What is the estimated slack time for activity D?

-What is the estimated standard deviation in the time for activity E?

An important assumption in PERT calculations is:

-What is the estimated mean time for project completion?

-What is the estimated mean time for activity E?

What is the estimated mean time for project completion?

The critical path for the network shown is: