To complete an addition to the Business Building, the activities in the file P15_33.xlsx must be completed (all times are in months). Assume that all activity times are normally distributed with the...

To complete an addition to the Business Building, the activities in the file P15_33.xlsx must be completed (all times are in months). Assume that all activity times are normally distributed with the means and standard deviations given in the file. The project is completed after Room 111 has been destroyed and the main structure has been built.

a. Estimate the probability that it will take at least three years to complete the addition.

b. For each activity, estimate the probability that it will be a critical activity.