James does not know any of the above information about delivery times. He resolves to take a sample of 100 delivery times. James will then calculate the mean of the 100 sampled delivery times (represented as X bar) and use this as an estimate of the mean population delivery time µ (which he does not know, but you do, is 28 minutes).
How to determine the mean and standard deviation of all the potential sample means?
Also what is the chance James's estimate of µ will be greater than 30 minutes?