We are interested in determining whether the variances of the sales at two music stores (A and B) are equal. A sample of 25 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. The test statistic is:
a. 1.50
b. 2.25
c. 1.56
d. .67

H0:

H1:

Now we can calculate the statistic like this:

And the best option would be:

b. 2.25

Step-by-step explanation:

Information given

represent the sample size A

represent the sample size B

represent the sample deviation for A

represent the sample deviation for B

Solution to the problem

We want to test if the variation for A it's equal to the variation for B, so the system of hypothesis are:

H0:

H1:

Now we can calculate the statistic like this:

And the best option would be:

b. 2.25

add an !

step-by-step explanation:

x = -4

step-by-step explanation:

- 20 - 4(x + 3) = 4x

=> -20 - 4x - 12 = 4x

=> - 32 -4x = 4x

=> -32 = 4x + 4x

=> - 32 = 8x

=> -32/8 = x

=> -4 = x