Case Scenario
Shannon Murray (President of the prestigious consulting firm of Murray, Knight & Whiting Consulting of Lakeland Florida) decided to have her own house built. To complete this project she had analyzed the following activities and had time values estimated for these activities. The first activity consisted of obtaining a loan, which included enlisting the services of a legal advisor. She estimated that this would take about 6 weeks, could take as long as 9 weeks but might also be accomplished in 3 weeks.
The next two activities could be done simultaneously. These are purchasing a lot on which to build the house and obtaining an architectural plan and related blueprints. The first activity was expected to take 3 weeks, could take as little as 2 weeks but might take as long as 10 weeks. The second activity was expected to take at least 6 weeks, possibly 12 weeks, but most likely 9 weeks.
Upon completing the previous two activities, the basement can be excavated. This was expected to take two weeks, no more or less. After the excavation, the basement walls and foundation could be poured, which was expected to take anywhere from 1 to 3 weeks but most likely 2 weeks.
The woodwork activity was next; it was expected to take about 8 weeks, no more or less. The electrical and plumbing work would occur during the foundation and woodwork activity and was not considered part of the network.
Finishing and painting was expected to take 6 weeks, but because of the unpredictability of the weather it would probably take 9 weeks and could take as long as 12 weeks.
Q1. Determine the expected activities times and standard deviations.
Q2. Compute the earliest start, latest start, earliest finish and latest finish time for each activity. Briefly explain early start, latest start, earliest finish, and latest finish.
Q3. Compute the slack time for each activity. Pick one of the activities with slack and briefly explain what it means.
Q4. Identify critical bottleneck activities where any delays must be avoided to prevent delay of the project completion. What is this called? Explain.
Q5. Determine the expected time required for completing the project and identify the slacks and critical activities?
Q6. What is the probability that the project will be completed in 40 weeks or less?
Q7. Find the number of weeks required to complete the project with probability .90%.