## Pert Estimate

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nazrulq
Contributor
Posts: 270
Joined: Sun Feb 26, 2017 6:06 am

### Pert Estimate

Q. Together with your team, you applied three-point estimation on a critical path which consists of two activities.
The following duration uncertainties are all calculated assuming a +/- 3 sigma confidence interval.The duration uncertainty - defined as pessimistic minus optimistic estimate - of the first activity is 18 days; the second estimate has an uncertainty of 24 days. applying the PERT formula for paths, what is the duration uncertainty of the entire path?

A. 21 days
B. 30 days
C. 42 days
D. No statement is possible from the information given.

Following is my justification.

Pert Estimate = (P+4M+0)/6 = (18+ 4M+24)/6 = (42+4M)
2. Std = P-O/6 = 24-18/6 = 1

3.Variance = Std^2 = 1

4.Range =Pert +/- X Std X=1 ( if nothing mentioned )

In Our case,

5.Range = Pert +/- 3 Std ( Our Case)

Range = Pert +/- 3

We have now 3 unknown but 2 equation so does n't give you anything. At lea

Pert Estimate = (P+4M+0)/6 = (18+ 4M+24)/6 = (42+4M)
Range = Pert +/- 3

Marked in Red are numbers of the unknowns!

That why Option 4 is the best choice! I guess!

Thank You.

Any further or different opinion will be highly appreciated.
ajaynit
Contributor
Posts: 116
Joined: Thu Dec 07, 2017 5:35 pm

### Re: Pert Estimate

sorry for responding without having any opinion on this but looking (Highlevel) at question couldnot resist to share that i am feeling a bit nervous thinking are these going to be PMP real exams question standards?