During a Test Period, an Experimental Group of 10 Vehicles

question 8

Multiple Choice

During a test period, an experimental group of 10 vehicles using an 85 percent ethanol-gasoline mixture showed mean CO₂ emissions of 667 pounds per 1000 miles, with a standard deviation of 20 pounds. A control group of 14 vehicles using regular gasoline showed mean CO₂ emissions of 679 pounds per 1000 miles with a standard deviation of 15 pounds. At α = 0.05, in a left-tailed test, the critical value to compare the means (assuming equal variances) is:

• A)-2.508
• B)-2.074
• C)-1.321
• D)-1.717

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Definitions:

Add

A mathematical operation that combines two or more amounts to get a total.

Simp

In colloquial use, shorthand for 'simpleton'; in internet culture, someone overly submissive to someone they're attracted to without reciprocation.

Conj

A conjunction is a logical operator that connects two statements in a way that the resulting statement is true only if both connected statements are true.

MP

Modus Ponens, a fundamental rule of logical deduction allowing one to derive a conclusion from a conditional statement and its antecedent.