During a test period, an experimental group of 10 vehicles using an 85 percent ethanol-gasoline mixture showed mean CO₂ emissions of 240 pounds per 100 miles, with a standard deviation of 20 pounds. A control group of 14 vehicles using regular gasoline showed mean CO₂ emissions of 252 pounds per 100 miles with a standard deviation of 15 pounds. A quick comparison of the sample variances suggests that the population variances are: A)probably equal. B)probably unequal. C)incomparable.

Question

Quizplus · Accepted Answer

The sample variances are close enough (400 for the experimental group and 225 for the control group) to suggest that the population variances are probably equal.

During a Test Period, an Experimental Group of 10 Vehicles