3. Dioxin includes a group of chemicals produced from burning and some types of manufacturing. The EPA uses 0.16 nanograms per cubic meter as its screening level, which is set to protect against increased risks of cancer and other adverse health effects. A manufacturer runs a plant and must shut down if the dioxin levels are found to be above the screening level. The air at the plant is appropriately sampled for several days. Does the manager have to shut down the plant? 3A. What is the appropriate test procedure? z-Test of the mean. t-Test of the mean. z-Test of the proportion. . None of these. 3B. What is the appropriate null hypothesis? U = 0.16 H S 0.16 u # 0.16 H 2 0.16 3C. What is the appropriate alternative hypothesis? H = 0.16 U 0.16 3D. Assume it should be a z-test. What decision would be made for a hypothesis test at significance 0.05 if you calculated a test statistic of 1.94? Do not reject the null. Reject the null. Sometimes reject the null. Do not reject the alternative