20 For the product development project in Exercise 19, consider the detailed time estimates given in Table 18. Note that the time estimates in Exercise 19 are equivalent to modal time estimates in this exercise.

TABLE 18 Time estimate (weeks)

Activity Optimistic Most likely Pessimistic A 1 3 4 B 1 1 2 C 4 5 9 D 1 1 1 E 4 6 12 F 1 1 2 G 1 2 3 H 6 8 10

a. Relabel your network in Exercise 19 to include (in place of ) and Use Eqs. (1)

and (2).

b. Compare total slacks and free slacks to Exercise 19.

c. Has the critical path changed?

d. Determine the following probabilities:

1. That the project will be completed in 22 weeks or less 2. That the project will be completed by the date obtained from the critical path calculations using as the activity durations 3. That the project takes more than 30 weeks to complete