The police department of Youbet, Michigan, is considering the purchase of new radar guns. On the average, the guns presently used by the department can detect a speeding vehicle at a distance of 2217 feet. In order to demonstrate the new radar guns, the manufacturer has allowed the Youbet police department to use the guns for a short period of time. A random sample of 20 days in action shows that the new guns can detect a speeding vehicle at 2230 feet (mean) with a standard deviation of 72 feet. If the old guns and the new guns are equally accurate, should the department purchase the new radar guns?