The Concentration of Hexane (A Common Solvent) Was Measured in Units

question 97

Multiple Choice

The concentration of hexane (a common solvent) was measured in units of micrograms per liter for a simple random sample of nineteen specimens of untreated ground water taken near a municipal landfill. The sample mean was $508.4$ with a sample standard deviation of 4.3. Sixteen specimens of treated ground water had an average hexane concentration of $506.1$ with a standard deviation of 4.7.
It is reasonable to assume that both samples come from populations that are approximatel normal. Can you conclude that the mean hexane concentration is less in treated water thar untreated water? Use the $\alpha = 0.01$ level of significance.

• A) No
• B) Yes

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Definitions:

Coefficient Of Determination

A statistic used in the context of predictive models that represents the proportion of variance in the dependent variable predictable from the independent variable(s), usually denoted as R².

Variation

The measure of the spread or distribution of a set of data points.

Standard Error Of Estimate

A measure that indicates the accuracy of predictions made in a regression analysis; it reflects the typical distance between observed and predicted values.

Coefficient Of Correlation

An analytical measure that identifies the strength and directionality of a linear relationship involving two factors.