The Stone River Textile Mill was inspected by OSHA and found to be in violation of a number of safety regulations. The OSHA inspectors ordered the mill to alter some existing machinery to make it safer (add safety guards, etc.); purchase some new machinery to replace older, dangerous machinery; and relocate some machinery to make safer passages and unobstructed entrances and exits. OSHA gave the mill only 35 weeks to make the changes; if the changes were not made by then, the mill would be fined $300,000.

The mill determined the activities in a CPM/PERT network that would have to be completed and then estimated the indicated activity times, as shown in the following table:

Activity Predecessor Time Estimates

(weeks)

Activity Activity Description a m b a Order new machinery — 1 2 3 b Plan new physical layout — 2 5 8 c Determine safety changes in existing machinery

— 1 3 5 Time Estimates

(weeks)

Activity Activity Description a m b d Receive equipment a 4 10 25 e Hire new employees a 3 7 12 f Make plant alterations b 10 15 25 g Make changes in existing machinery c 5 9 14 h Train new employees

d, e 2 3 7 i Install new machinery

d, e, f 1 4 6 j Relocate old machinery

d, e,

f, g 2 5 10 k Conduct employee safety orientation h, i, j 2 2 2 Construct the project network for this project and determine the following:

a. Expected activity times

b. Earliest and latest activity times and activity slack

c. Critical path

d. Expected project duration and variance

e. The probability that the mill will be fined $300,000

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