Exhibit 11-2
We are interested in determining whether or not the variances of the sales at two music stores (A and B) are equal. A sample of 26 days of sales at store A has a sample standard deviation of 30 while a sample of 16 days of sales from store B has a sample standard deviation of 20.
-Refer to Exhibit 11-2. The p-value for this test is
A)between 0.05 and 0.10
B)between 0.10 and 0.2
C)between 0.2 and 0.3
D)None of these alternatives is correct.

Question

Quizplus · Accepted Answer

Since we do not know the significance level of the test, we will use a two-tailed test.

The test statistic is given by:

F = s1^2 / s2^2

where s1 is the sample standard deviation of the sales at store A and s2 is the sample standard deviation of the sales at store B.

Substituting the given values, we get:

F = 30^2 / 20^2 = 2.25

The degrees of freedom for the numerator and denominator are 25 and 15, respectively.

Using a calculator or a statistical software, we can find that the p-value for this test is between 0.10 and 0.2. Thus, the best choice is B.

Exhibit 11-2 We Are Interested in Determining Whether or Not the Variances