The U. S. Department of Transportation provides the number of miles that residents of the largest metropolitan areas travel per day in a car. Suppose that for a random sample of Buffalo residents the mean is miles a day and the standard deviation is miles a day, and for an independent random sample of Boston residents the mean is miles a day and the standard deviation is miles a day. Round your answers to one decimal place. a. What is the point estimate of the difference between the mean number of miles that Buffalo residents travel per day and the mean number of miles that Boston residents travel per day