Problem:
General Motors is planning a new ad campaign targeted at aging Boomers who seek roominess, comfort and elegance.
Based on past experience, Task #1 usually takes days 52. If things do not go as planned, the task will take 74 days. If things go very well, Task #1 can be completed in 40 days.
Task #2 usually takes 87 days. Task #2 will be completed in 73 days if everything goes well. If there is a glitch, it will take 104 days. Normally, Task #2 cannot start until task #1 has been completed.
Task #3 normally takes 75 days under all conditions/scenarios. Task #3 cannot be started until task #2 has been completed.
Task #4 cannot start until Task #3 has been completed. Task #4 normally takes 72 days. For Task #4, the best and worst case scenarios are 64 days and 98 days, respectively.
Under normal circumstances, it takes 68 days to complete Task #5. The best and worst case scenarios are 53 and 71 days, respectively.
Task #6 normally takes 118 days. Under ideal conditions, it can be completed in 97 days. The pessimistic time estimate is 127 days. Task #6 cannot start until Task #4 is completed.
Required to answer:
Q1. What is the expected number of days to complete this project.
Q2. What is the variance for the project?
Q3. What is the probability that the project will take more than 390 days to complete?