Activity a m b Immediate predecesso A 3 6 9 - B 2 4 6 - C 6 7 8 - D 1 2 3 B E 2 4 12 C,D F 6 8 10 A,E average time Variance a) Compute average time and a time of each activity b) What is the probability that path C-E-F will be completed within 22 days. Compute the z value. c) What is the probability that path B-D-E-F will be completed within 21 days. Compute the z value.