Suppose you manage a plant that purifies its liquid waste and discharges the water into a local river. An EPA inspector has collected water specimens of the discharge of your plant and also water specimens in the river upstream from your plant. Each water specimen is divided into five parts, the bacteria count is read on each, and the mean count for each specimen is reported. The average bacteria counts for each of six specimens are reported in the following table.
(a) Please test, at the significance level of 0.05, whether the mean bacteria count for the plant discharge exceeds that for the upstream location.
Plant Discharge Upstream
30.1 29.7
36.2 30.3
33.4 26.4
28.2 27.3
29.8 31.7
34.9 32.3