A study by the U.S. Public Research Interest Group found that in Massachusetts bank customers were charged lower fees than the national average for regular checking accounts, NOW accounts, and savings accounts. For regular checking accounts the Massachusetts mean was $190.06 per year, while the national mean was $201.94 (Boston Globe, Aug. 9, 1995). The referenced article did not explain how these averages were determined other than to say the national average was estimated from a sample of 271 banks in 25 states. Prepare a report that explains in detail how Massachusetts' mean could have been estimated. There are 245 banks in Massachusetts. Your answer should include a sampling plan, a measurement plan, and a calculation formula.