## Confidence Level

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vaishnavi
Posts: 5
Joined: Sun Mar 19, 2017 6:16 pm

### Confidence Level

Hi,

Critical path of the project has 3 activities in sequence . Activity A has optimistic estimate as 8,pessimistic as 16 and most likely as 12.Activity B has optimistic estimate as5,Pessimistic estimates as15 and most likely estimate as 0.Activity C has optimistic estimate as 10,pessismistic estimate as 20 and most likely as 15.What is the confidence that project would finish between 34-40 days?

Total project variance comes out to be 9.8 and square root of variance =2.7.Not sure how to solve further - Can you please assist?
VCAB
Participant
Posts: 73
Joined: Wed Dec 21, 2016 4:26 pm

### Re: Confidence Level

formula
Confidence Interval= Project Mean +/- 1SD will give you a range at 68% confidence
Project Mean +/- 2SD will give you a range at 95.5% confidence
Project Mean +/- 3SD will give you a range at 99.97% confidence
nazrulq
Contributor
Posts: 266
Joined: Sun Feb 26, 2017 6:06 am

### Re: Confidence Level

1 sigma =68.26%
2 Sigma =95.46%
3 Sigma =99.73%
6 Sigma = 99.99%

Thanks.
vaishnavi
Posts: 5
Joined: Sun Mar 19, 2017 6:16 pm

### Re: Confidence Level

Thanks - So answer will be .68? Since SD of the project is 2.7?

a).68
b).997
c).95
d).88
manishpn
Expert
Posts: 2406
Joined: Sat Jan 04, 2014 3:55 pm

### Re: Confidence Level

vaishnavi wrote:Hi,

Critical path of the project has 3 activities in sequence . Activity A has optimistic estimate as 8,pessimistic as 16 and most likely as 12.Activity B has optimistic estimate as5,Pessimistic estimates as15 and most likely estimate as 0.Activity C has optimistic estimate as 10,pessismistic estimate as 20 and most likely as 15.What is the confidence that project would finish between 34-40 days?

Total project variance comes out to be 9.8 and square root of variance =2.7.Not sure how to solve further - Can you please assist?

Such questions are rare in PMP , do not spend too much time on those
Br,
Manish P
PMP, PMI - ACP, SAFe Agilist
http://www.izenbridge.com/blog/7-effect ... ification/