The Safe Drinking Water Act, which was passed in 1974, allows the Environmental Protection Agency (EPA) to regulate the levels of contaminants in drinking water. The EPA requires that water utilities give their customers water quality reports annually. These reports include the results of daily water quality monitoring, which is performed to determine whether drinking water is safe for consumption.
A water department tests for contaminants at water treatment plants and at customers laps. These contaminants include microorganisms, organic chemicals, and inorganic chemicals such as cyanide. Cyanide’s presence in drinking water is the result of discharges from Steel, plastics, and fertilizer factories. For drinking water, the maximum contaminant level of cyanide is 0.2 part per million.
As part of your job for your city’s water department, you are preparing a report that includes an analysis of the results shown in the figure at the right. The figure shows the point estimates for the population
3. What Do You Think?
The confidence interval for Year 2 is much larger than the other years. What do you think may have caused this larger confidence level?
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Elementary Statistics: Picturing the World (6th Edition)
- What do people actually order at Chipotle? How healthy is a normal Chipotle meal? Chipotle and other relatively new fast casual chains like Shake Shack, Potbelly and Five Guys typically promote themselves as having healthier menu choices than the traditional fast food outlets like McDonald's, Taco Bell, Burger King, etc.The recommended daily calorie intake for most adults is 1,600 to 2,400. The histogram below shows the calories in approximately 3,000 meals ordered from Chipotle on Grubhub.While the histogram is not perfectly symmetric (there is mild right skewness), it is close enough to being symmetric and bell-shaped to justify using the 68-95-99.7 rule. Suppose the distribution of calories in a Chipotle meal can be considered symmetric and bell-shaped with mean 1079 calories and standard deviation 296 calories. Use the 68-95-99.7 rule to answer the following questions.a. What is the approximate percentage of the Chipotle meals that have between 487 and 1671 calories?b. The middle…arrow_forwardThe table below gives adult wine consumption.arrow_forwardThe goal of a research study is to provide an accurate picture of the status or characteristics of a situation or phenomenon. This study is best described as: A. Explanatory B. Descriptive C. Predictive D. Confirmatoryarrow_forward
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