1. What is the critical path?

2.You can launch after final checks are complete. How many weeks do you expect final checks to be complete?

3.How many weeks do you need in order to make sure the project is completed with 90%probability?

You're a project manager for SpaceX, and it's your job to oversee the construction of a new prototype rocket. You've worked with your engineering teams and put together the following set of activities, and their predecessors. You're able to move very quickly, so all times are in weeks. You've asked your engineers to give you mean activity times, along with standard deviations and variances. Two teams instead gave you 3 time estimates: optimistic (a), most likely (m), and pessimistic (b). Node a b c d a e Activity Predecessor am b Mean Std Dev Var Build engines 1 3 5 Build life support 3 1/2 1/4 Build body 4 5/6 25/36 Test engines 3 1/2 1/4 Assemble propulsion d 2 5 8 Meet with NASA be 2 1/6 1/36 Assemble spaceship b,c,e 6 5/6 25/36 Clarify NASA questions f 1/2 1/4 Cargo loading 4 1/2 1/4 Final checks hi 2 1/2 f 4 h i j 1/4