Let 1 denote the true average tread life for a premium brand of P205/65R15 radial tire and let 2 denote the true average tread life for an economy brand of the same size. Test H0 : 1 2 = 5000 versus Ha : 1 2 6= 5000 at level .01 using the following data: n1 = 45, x1 = 42,500,1 = 2200,n2 = 45, x2 = 36,800,2 = 1500