Question: In an air pollution study performed at an experiment station, the following amounts of suspended benzene-soluble organic matter (in micrograms per cubic meter) were obtained for eight different samples of air: 2.2, 1.8, 3.1, 2.0, 2.4, 2.0, 2.1, 1.2. Assuming that the population is normal, construct a 95% confidence interval for the corresponding true mean.