2. A construction project is shown in the table below with the activities, their predecessor activities, and three time estimates (optimistic a, most likely m, and pessimistic b), along with the expected time te and the standard deviation for each activity. Draw the network diagram, find the critical path, and the expected project completion time. What is the probability that the project can be completed in 21 days? Predecessors Time: a m none none Activity A B D E F G H I J none A D B, E B, C, E F G HI 1 2 2 1 2 1 3 2 3 1 3 3 4 3 5 2 6 4 4 2 b 5 5 7 4 8 2 8 5 6 4 te 3 3.167 4.167 2.833 5 1.833 5.833 3.833 4.167 2.167 var. 0.445 0.25 0.694 0.25 1.0 0.028 0.694 0.25 0.25 0.25