10. 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 alpha = .10, the critical values are: Select one: 3.73 and .228 2.51 and 3.67 3.07 and .398 3.07 and .357

3.07 and 0.357

Step-by-step explanation:

To solve the problems above, we use the F- distribution or statistic to test the equality of variance in a two tailed test.

We can employ the excel function :

F.INV.RT(alpha, deg_of _freedom1, deg_of_freedom2) to get the right tail and

F. INV(alpha, deg_of _freedom1, deg_of_freedom2)

alpha = 0.1

For a two tailed test ;

Alpha = 0.1 ÷ 2 = 0.05

Deg_of freedom1 = (number of observation1 - 1)

Deg_of freedom1 = 13 - 1 = 12

Deg_of freedom2 = (number of observation2 - 1)

Deg_of freedom2 = 10 - 1 = 9

Right tail:

F.INV.RT(0.05,12,9) = 3.07

F.INV(0.05,12,9) = 0.357

1) 2/5

2) zero=0/1

3) zero=0/2

4) -4/5

5) undefined=3/0