Question- PERT

Submitted by sumedha82 on Tue, 09/13/2011 - 15:07

Another question from oliver.....Pls help (Apologies for the format) A project manager made 3-point estimates on a critical path and found the following results: Assuming ±3 Sigma precision level for each estimate, what is the standard deviation of the allover path?
		App. 4.2 days
		App. 5.2 days
		App. 6.2 days
		You can not derive the path standard deviation from the information given.

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General Discussion

bheemineni

Wed, 09/14/2011 - 02:22

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Answer is “B” = 5.2 days

Task Variance = [(P-O)/6]²

Project Standard deviation= √Sum of task Variances

Standard deviation of the allover path = √ [Var A + Var B + Var C + Var D + Var E]

= √ [(24-12)/6 ²+ (14-8)/6 ²+ (27-15)/6 ²+ (28-10)/6 ² + (35-17)/6 ²]

= √ [2²+ 1²+ 2²+3²+3²]

= √ 27 = 5.196

Sorry if the symbols are not clear. I hope it still makes sense.

Vijay Bheemineni, MS, PMP, ITIL

Wed, 09/14/2011 - 06:49

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I despise Oliver Lehman's questions a whole lot. Did it during my prep but felt that during the actual exam, it was a serious waste of my time. If its anything to go by, you will not get such questions that require such detailed calculations. I have liaised with other colleagues and from our point of view, Oliver's questions just don't have any applicability to the actual exam.

sumedha82

Wed, 09/14/2011 - 10:07

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