A researcher wants to test to see if husbands are significantly older than their wives. For this he collects the ages of husbands and pairs them with the ages of their respective wives for a random set of married couples.Suppose that data were collected for a random sample of12

couples, where each difference is calculated by subtracting the age of the wife from the age of the husband. Assume that the ages are normally distributed. What type of test is this hypothesis test?

Select the correct answer below:

This is a right-tailed test because the alternative hypothesis isH

a

:

d

>0

.

This is a two-tailed test because the alternative hypothesis isH

a

:

d

0

.

This is a right-tailed test because the alternative hypothesis isH

a

:

d

<0

.

This is a left-tailed test because the alternative hypothesis isH

a

:

d

<0

.

This is a left-tailed test because the alternative hypothesis isH

a

:

d

>0

.