18. Refer to the previous question. Suppose a partner in Keone Technology does not be- lieve the time estimates for each activity can be specified with certainty. Instead, he prefers to specify a minimum, most likely, and maximum number of days for each activity. These estimates are given in the following table. Activity Minimum Most Likely Maximum 5 10 20 16 19 27 10 13 18 8 14 14 21 a. Use PERT to identify the expected time and variance for each activity. b. What is the critical path? What is the expected time and variance for this path? c. Assume the distribution of the completion time for the critical path is normally distributed. What is the probability that it will take at least 40 days to complete the project? 19. Refer to the previous question. `reate a spreadsheet model to simulate the comple