# Question: Let X and Y equal the hardness of the hot

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 μX − μY, assuming that the distributions of X and Y are N(μX, σ2X) and N(μY, σ2Y), 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?

(a) Calculate the sample means and the sample variances of these data.

(b) Construct a 95% confidence interval for μX − μY, assuming that the distributions of X and Y are N(μX, σ2X) and N(μY, σ2Y), 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?

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