For large U.S. companies, what percentage of their total income comes from foreign sales? A random sample of technology companies (IBM, Hewlett- Packard, Intel, and others) gave the following information. t Technology companies, % foreign revenue: x,; n, = 16 62.8 55.7 47.0 59.6 55.3 41.0 65.1 51.1 53.4 50.8 48.5 44.6 49.4 61.2 39.3 41.8 Another independent random sample of basic consumer product companies (Goodyear, Sarah Lee, H.J. Heinz, Toys 'R' Us) gave the following information. Basic consumer product companies, % foreign revenue: x,; n, = 17 28.0 30.5 34.2 50.3 11.1 28.8 40.0 44.9 40.7 60.1 23.1 21.3 42.8 18.0 36.9 28.0 32.5 In USE SALT Assume that the distributions of percentage foreign revenue are mound-shaped and symmetric for these two company types. (a) Use a calculator with mean and standard deviation keys to calculate X1 , S1, X2, and $2. (Round your answers to four decimal places.) X 1 S X 2 S ? (b) Let u, be the population mean for x, and let u, be the population mean for x, . Find a 95% confidence interval for , - #, . (Round your answers to two decimal places.) lower limit % upper limit