Suppose that the activity times are random variables with a constant coefficient of variation of 0.2. (The coefficient of variation is the ratio .) Assume that the times given in Problem 3 are the mean activity times.

a. Compute the standard deviation of each of the activity times.

b. Find the mean and the variance of the path with the longest expected completion time.

c. Using the results of part (b), estimate the probability that the project is completed within 20 weeks.

d. Using the results of part (b), estimate the number of weeks required to complete the project with probability .85.