### Pert Estimate

Posted:

**Mon Jan 01, 2018 8:49 pm**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.

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.