Develop a project network for this problem b Determine the c
Develop a project network for this problem.
b- Determine the critical path for the campaign project and the expected project completion time. (Use the
expected time for the activity completion time).
c- Determine the probability that the project will be completed in less than 34 days.
d- Determine the probability that the project will take more than 29 days
Solution
Let us consider the below network diagram for which completion time is calculated :
Activity
Predecessor
Optimistic Estimates (Days)
Most Likely Estimates (Days)
Pessimistic Estimates (Days)
Expected Duration
(a+4b+c)
6
Variance
((b-a)/6)2
A
None
1
2
4
2.2
0.3
B
A
3
5
8
5.2
0.7
C
B
2
4
5
3.8
0.3
D
B
2
3
6
3.3
0.4
E
B
1
1
1
1.0
0.0
F
C,D
2
4
6
4.0
0.4
G
D,E
2
3
4
3.0
0.1
H
F,G
1
2
5
2.3
0.4
I
G
4
5
9
5.5
0.7
J
H,I
.5
1
3
1.3
0.2
Possible Paths
Path
Total
Path 1
A+B+C+F+H+J
18.8
2.2+5.2+3.8+4.0+2.3+1.3
Path 2
A+B+D+F+H+J
18.3
2.2+5.2+3.3+4.0+2.3+1.3
Path 3
A+B+D+G+H+J
18.6
2.2+5.2+3.3+3.0+2.3+1.3
Path 4
A+B+D+G+I+J
20.5*
2.2+5.2+3.3+3.0+5.5+1.3
Path 5
A+B+E+G+I+J
18.2
2.2+5.2+1.0+3.0+5.5+1.3
Critical Path is 20.3
Project Variance= Sum of variances of activities on the critical path
We know the standard deviation is just the square root of the variance
Project Standard Deviation = sqrt(2.4)=1.55
The project’s expected completion date is 20.5 weeks
Probability of Project Completion:
Z= Due Date - Expected Date of Completion/Standard Deviation
=22-20.5/1.55 =0.967
therefore Z= 83.33%
That means there is a 83.3% probability this project can be completed in 22 weeks or less
* Please Note : It is an assumed example of network analysis since question does not provide network diagram data
| Activity | Predecessor | Optimistic Estimates (Days) | Most Likely Estimates (Days) | Pessimistic Estimates (Days) | Expected Duration (a+4b+c) 6 | Variance ((b-a)/6)2 |
| A | None | 1 | 2 | 4 | 2.2 | 0.3 |
| B | A | 3 | 5 | 8 | 5.2 | 0.7 |
| C | B | 2 | 4 | 5 | 3.8 | 0.3 |
| D | B | 2 | 3 | 6 | 3.3 | 0.4 |
| E | B | 1 | 1 | 1 | 1.0 | 0.0 |
| F | C,D | 2 | 4 | 6 | 4.0 | 0.4 |
| G | D,E | 2 | 3 | 4 | 3.0 | 0.1 |
| H | F,G | 1 | 2 | 5 | 2.3 | 0.4 |
| I | G | 4 | 5 | 9 | 5.5 | 0.7 |
| J | H,I | .5 | 1 | 3 | 1.3 | 0.2 |

