6.9 Env. 6.9 The study of concentrations of atmospheric trace metals in isolated areas of the world has received considerable attention because of the concern that humans might somehow alter the climate of the earth by changing the amount and distribution of trace metals in the atmos- phere. Consider a study at the South Pole, where, over a 2-month period, seventy air samples were obtained. In thirty-five of the samples, the amount of magnesium was determined. In the remaining thirty-five samples, the amount of europium was determined. Sample Size Sample Mean Sample Standard Deviation Magnesium 35 1.0 2.21 Europium 35 17.0 12.65 a. What are the populations of interest in this study? b. Is there significant evidence of a difference in the mean magnesium and Europium levels? Use a = .05. c. What is the level of significance of your test? d. Estimate the mean levels of magnesium and Europium using a 95% confidence interval