Iowa Is an Agricultural State with a Large Number of Rivers

question 25

Essay

Iowa is an agricultural state with a large number of rivers. The use of chemical pesticides and increasing size of livestock herds has created a concern for the water quality in the state. A researcher recently surveyed the rivers of Iowa and analyzed the concentrations of certain chemicals at different locations in the watersheds of Iowa. The cumulative relative frequency plot below displays the distribution of Nitrogen concentrations along the Skunk River. (a)Approximately what percent of the Nitrogen concentration measurements are less than 10 mg/L?
(b)Approximately what percent of the Nitrogen concentration measurements are 12 mg/L or more?
(c)50% of the Nitrogen concentration measurements lie below what approximate value?

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Definitions:

Freshmen

First-year students in a high school, college, or university.

Probability

A quantification of the probability of an event happening, indicated by a value ranging from 0 to 1, with 0 meaning the event cannot happen and 1 meaning the event is certain to happen.

Standard Deviation

A statistic that measures the dispersion or variability of a dataset relative to its mean, indicating how spread out the values are.

Simple Random Sample

An evenly selected portion of a wider population, with each participant having an equal opportunity to be chosen.