We want to decide whether to employ a human operator or buy a machine to paint steel beams with a rust inhibitor. Steel beams are produced at a constant rate of one every 11 minutes. A skilled human operator takes an average time of 600 seconds to paint a steel beam, with a standard deviation of 30 seconds. An automatic painter takes on average 30 seconds more than the human painter to paint a beam, but with a standard deviation of only 10 seconds. Estimate the expected waiting time in queue of a steel beam for each of the operators, as well as the expected number of steel beams waiting in queue in each of the two cases. Comment on the effect of variability in service time.