A manufacturing project has five independent phases whose completion must be sequential. The time to complete each phase is a random variable. The mean and standard deviation of the time for each...

A manufacturing project has five independent phases whose completion must be sequential. The time to complete each phase is a random variable. The mean and standard deviation of the time for each phase is shown below. (a) Find the expected completion time. (b) Make a 2-sigma interval around the mean completion time (μ ± 2σ).