Question:
a. The following probability distributions relate to the completion times, in weeks, TA and TB of two independent activities, A and B respectively.
|
t
|
Pr(TA =t)
|
|
2
|
0.20
|
|
4
|
0.35
|
|
6
|
0.25
|
|
8
|
0.20
|
|
t
|
Pr(TB =t)
|
|
3
|
0.25
|
|
5
|
0.50
|
|
7
|
0.25
|
The activities A and B form a important phase of a project.
i). Derive the probability distribution of the completion times of this phase if the two activities are undertaken in:
a. series
b. parallel
ii) For each of the distribution in (i) above, calculate their relevant statistics.
A task is known to have the following time to completion (in days), T and cost, C probability distribution, respectively: T ≈ N(20,25)
The distribution of C is conditional on T and is given by:
N(1500,4900), T ≤ 22;
C ≈ N(1800,4900), 22<T ≤ 25;
N(2300,4900), 25< T.
Calculate:
i). Pr(T≤ 25);
ii Pr(C≤ 2200).