After a heavy storm, the waste water holding tanks at a waste water treatment plant on the New River overflowed dumping 1,000,000 gallons of sewage into the New River. You are part ofthe New River Citizen Watch Group, which monitors the health of portions of the New River for government agencies like the EPA and USDA. This sewage discharge event causes your group to wonder if the event has had a negative impact on the quality of the water downstream of the waste water treatment plant. To test your group\'s idea that the sewage has negatively impacted water quality, you measure in triplicate the EPT of a site upstream of the waste water treatment plant and a site downstream of the waste water treatment plant. You calculate the mean 9% EPT of both sites and the 95% confidence intervals of both samples. Your results are shown below. Use this scenario and data to answer the following questions. 120 1000 60 Upstream site Downstream site
In an experiment or research, there are three different variables which must be considered. These are the independent variable, the dependent variables, and the constant variable. Independent variable is that which is tested by the investigator and is not affected by changes in other variables.
Answer: d. The collection sites (upstream and downstream of the wastewater treatment plant)
The existence of the collection sites will not change whether there has been sewage discharge or not.
Note: The % EPT reflects the better quality of water. Higher the %EPT, the water quality is superior, as is indicated in the bar graph.
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