In September, demand for industrial furnace boilers at a large plumbing supply warehouse has a mean of 7 boilers with a standard deviation of 2 boilers. The warehouse pays a unit cost of $2,225 per boiler plus a fee of $500 per month to act as dealer for these boilers. Boilers are sold for $2,850 each. (a) Find the mean and standard deviation of September profit (revenue minus cost). (b) Which rules did you use?
A certain outpatient medical procedure has five steps that must be performed in sequence. (a)Â Assuming that the time (in minutes) required for each step is an independent random variable, find the mean and standard deviation for the total time. (b) Why might the assumption of independence be doubtful?