6. A small project is composed of seven activities whose time estimates are listed in the following table. Activities are identified by their beginning (i) and ending (j)

node numbers.

Estimated Duration (Wks)

i j Optimistic Most Likely Pessimistic

a. Using the classic PERT model, what is the probability that the project will be completed two weeks earlier than its expected duration?

b. Based on the classic PERT model, what due date has a 90 percent chance (or greater) of being met?

c. A major criticism of the classic PERT model is that it relies only on the longest expected path in the precedence network. One possible solution that has been suggested is to use both the longest path and the second-longest path to calculate the expected project duration. If this approach was used in this problem, what is the probability that the project will be completed within 16 weeks?