To finish this scenario, use the Confidence Interval Calculator Sheets 1,2,3.
The Sacred Grounds coffee shop in Dead horse, AK, is considering changing its coffee brewing units with new German brewers. You have been assigned to investigate this proposal. Make a 99% confidence interval for the average yield (cups per pound) for the new German coffee brewer. The margin of error should be no bigger than .3 (three-tenths of a cup). Based on experience with the present system, your best guess for the population standard deviation is 1.2 cups. How big a sample do you require?