Example 8.6.2 Comparing Copper Ores. Suppose that a random sample of eight specimens of ore is collected from a certain location in a copper mine, and the amount of copper in each of the specimens is measured in grams. We shall denote these eight amounts by … and shall suppose that the observed values are such that … and … Suppose also that a second random sample of 10 specimens of ore is collected from another part of the mine . We shall denote the amounts of copper in these specimens by … and shall suppose that the observed values in grams are such that … and … Let … denote the mean amount of copper in all the ore at the first location in the mine; let … denote the mean amount of copper in all the ore at the second location ; and suppose that the hypotheses (8.6.8) are to be tested.