The U.S. Department of Transportation provides the number of miles that residents of the 75 largest metropolitan areas travel per day in a car. Suppose that for a simple random sample of 70 Buffalo residents the mean is 22.7 miles a day and the standard deviation is 8.5 miles a day, and for an independent simple random sample of 30 Boston residents the mean is 18.9 miles a day and the standard deviation is 7.9 miles a day.