The amount of sewage and industrial pollutants dumped into a body of water affects the health of the water by reducing the amount of dissolved oxygen available for aquatic life. Suppose that weekly readings are taken from the same location in a river over a 2-months period. Conduct a statistical test of the research hypothesis that the mean dissolved oxygen content is less than 5.0 parts per million, a level which some scientists think is marginal for supplying enough dissolved oxygen for fish. 5.1, 4.9, 5.6, 4.2, 4.8, 4.5, 5.3, 5.2, 8. (Ott 1993)