a coin-operated soft drink machine was designed to discharge, on average, 7 oz of beverage per cup. in a test of the machine, 10 cupfuls of beverage were drawn from the machine and measured. the average and sd of the ten measurements were 7.1 oz and 0.12 oz, respectively. assume that the histogram of beverage discharge from this machine roughly follows a normal curve. does this machine discharge more than 7.0 oz or does the difference represent chance variation?