Based on a Random Sample of 13 Tire Changes, the Mean

Multiple Choice

Based on a random sample of 13 tire changes, the mean time to change a tire on a Boeing 777 has a mean of 59.5 minutes with a standard deviation of 8.4 minutes. For 10 tire changes on a Boeing 787, the mean time was 64.3 minutes with a standard deviation of 12.4 minutes. To test for equal variances in a two-tailed test at α = .10, the critical values are:

A) 3.73 and 0.228
B) 2.51 and 3.67
C) 3.07 and 0.398
D) 3.07 and 0.357