Let X and Y equal the hardness of the hot and cold water, respectively, in a campus

Question:

Let X and Y equal the hardness of the hot and cold water, respectively, in a campus building. Hardness is measured in terms of the calcium ion concentration (in ppm). The following data were collected (n = 12 observations of X and m = 10 observations of Y):

(a) Calculate the sample means and the sample variances of these data.
(b) Construct a 95% confidence interval for Î¼X ˆ’ Î¼Y, assuming that the distributions of X and Y are N(Î¼X, Ïƒ2X) and N(Î¼Y, Ïƒ2Y), respectively.
(c) Construct box plots of the two sets of data on the same graph.
(d) Do the means seem to be equal or different?