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

question 21

Multiple Choice

The concentration of hexane (a common solvent) was measured in units of micrograms per liter for a simple random sample of thirteen specimens of untreated ground water taken near a municipal landfill. The sample mean was 424.2 with a sample standard deviation of 6.5. Fourteen specimens of treated ground water had an average hexane concentration of 246.0 with a standard deviation of 5.9. It is reasonable to assume that both samples come from populations that are approximately normal. Construct a 99% confidence interval for the reduction of hexane concentration after treatment.

• A)(175.6, 180.8)
• B)(175.1, 181.3)
• C)(176.7, 179.7)
• D)(170.9, 185.5)

---

Definitions:

Positive Correlation

The incidence of one event increases when the second one increases.

Occurrence of Events

The happening or taking place of incidents or actions, often considered in terms of their frequency or significance.

Analogies

A form of reasoning or argumentation in which similarities between two different things are drawn to explain or clarify a concept.

Refute Arguments

The process of logically disproving or countering the claims or premises of an argument.