During a test period, an experimental group of 10 vehicles using an 85% 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. To test for equal variances in a two-tailed test at a = .10, the critical values are
A. 0.326 and 2.71
B. 0.420 and 2.16
C. 0.246 and 4.19
D. 0.338 and 3.94
The value of the test statistic for a test of equal variances is
A. 1.78
B. 1.33
C. 1.05
D. 3.00