Suppose that a random sample of 800 early replacement buyers yields a mean number of dealers visited of 1 = 3.3, and that a random sample of 500 late replacement buyers yields a mean number of dealers visited of 2= 4.5. Assuming that these samples are independent: (a) Let 1 be the mean number of dealers visited by early replacement buyers, and let 2 be the mean number of dealers visited by late replacement buyers. find out a 95 percent confidence interval for 2 - 1. Assume here that 1 = .71 and 2 = .66.