Question

Case 4: Alfred Lowenstein made a serious mistake (20 points) Alfred Lowenstein is the president of the research division for Concrete Co. a major pre-stressed concrete development company. His most important project coming up is the development of a new mix for concrete that is economical yet, provides the required strength. He has identified 19 groups in his division, which will need to carry out different phases of this research and development project Referring to the work to be done by the respective groups as activities, A, B, . S; the precedence relationships for which these groups need to do their work along with the estimates for the duration (in weeks) of the activities are shown in the following table ActivityImmediate Predecessor Optimistic Most Likely essimistic Estimate Estimate Estimate 12 30 25 A, B. C A, B, C D, L. K M, E 10 Figure 5: Project details To meet the construction project deadline, Concrete Co.'s CEO has informed Alfred that he wants the mix ready within 60 weeks if possible. Alfred knows very well that there is considerable uncertainty about how long each group will need to its work. What is the probability that the project will be completed within 60 weeks? Identify all the paths in the project network and for each of these paths, compute the probability of competing these paths within 60 weeks? [10 points Alfred realized that he has made a serious mistake in his scheduling. Group K can be on board only after 24 weeks. So he quickly revised his full project analysis to take this into account. [10 points]

Answer 1

ANS PART 1

Optimistic = a Most likely = m Pessimistic = b critical path E - 0 - P - Q - R = 49.34 Probability of completing project within 60 weeks (x = 60) z = x - mu/3 3 squareroot 7.72 = 2.78 \r\n z = 60 - 49.34/2.78 = 3.83 Probability (z) = 3.83 Probability = 99.9 %