In: Statistics and Probability
M5_A2. The Mountaineers American Bank of Carolina is planning to install a new computerized accounts system. Bank management has determined the activities required to complete the project, the precedence relationships of the activities, and the activity time estimates, as shown in the table below.
activity | optim time (a) | most likely time (m) | pessim time (b) | immediate Pred |
A | 5 | 8 | 17 | --- |
B | 3 | 12 | 15 | --- |
C | 4 | 7 | 10 | A |
D | 5 | 8 | 23 | A |
E | 1 | 1 | 1 | B,C |
F | 1 | 4 | 13 | B,C |
G | 3 | 6 | 9 | D,E |
H | 1 | 2.5 | 7 | D,E |
I | 1 | 1 | 1 | H |
J | 2 | 2 | 2 | F,G |
K | 5 | 8 | 11 | I,J |
Calculate the expected duration and variances for each activity. Use the expected durations to develop a project network for this problem and answer the following questions (Note: when using the Z tables –round your Z values to two decimal places before getting the probabilities from the tables. DO NOT round standard deviations prior to calculating Z values)
NOTE: Enter probabilities as decimals (i.e 92.31% should be entered as 0.9231)
a) What activities are on the critical path? (Select all activities that are on critical path)
b) How many days will it take to complete the project?
c) What is the total variance of the project (i.e. the activities that are on the critical path)? (Enter
to two decimal places)
d) What is the total standard deviation of the project (i.e. the activities that are on the critical
path)? (Enter standard deviation to three decimal places)
e) What is the probability that the project will be completed in less than 34 weeks to complete?
(Enter probability to four decimal places from distribution tables)
f) What is the probability that the project will take more than 29 weeks to complete? (Enter
probability to four decimal places from distribution tables)
g) What is the probability that the project will between 30 and 38 weeks to complete? (Enter
probability to four decimal places from distribution tables)
Activity | a | m | b | estimated time(ei) | SD | Variance |
A | 5 | 8 | 17 | 9 | 2 | 4 |
B | 3 | 12 | 15 | 11 | 2 | 4 |
C | 4 | 7 | 10 | 7 | 1 | 1 |
D | 5 | 8 | 23 | 10 | 3 | 9 |
E | 1 | 1 | 1 | 1 | 0 | 0 |
F | 1 | 4 | 13 | 5 | 2 | 4 |
G | 3 | 6 | 9 | 6 | 1 | 1 |
H | 1 | 2.5 | 7 | 3 | 1 | 1 |
I | 1 | 1 | 1 | 1 | 0 | 0 |
J | 2 | 2 | 2 | 2 | 0 | 0 |
K | 5 | 8 | 11 | 8 | 1 | 1 |
From the given data we have below table
Different possible paths
areBelow is the PERT diagram
Paths | Duration |
ADHIK | 31 |
ADGJK | 35 |
ACEHIK | 29 |
ACEGJK | 33 |
ACFJK | 31 |
BEHIK | 24 |
BEGJK | 28 |
BFJK | 26 |
Hence critical path is ADGJK with duration 35 days
(A) Activities on critical path are A, D, G, J and K
(B) It will take 35 days to complete the project
(C) Total variance of the project = sum of variance of the activities on critical path = 15 days
(D) std. dev. = sqrt(15) = 3.873 days
Please hit like button...