If a researcher wishes to determine whether there is evidence that the mean family income in the U. S. is greater than $30,000, then:

A. a one-tailed test should be used, in which the region of rejection is in the left (lower tail)

B. a one-tailed test should be utilized, in which the region of rejection is in the right (upper tail)

C. a two-tailed test should be used either a one-tailed or a two-tailed test could be used

B) a one-tailed test should be utilized, in which the region of rejection is in the right (upper tail)

Step-by-step explanation:

Explanation:-

one tailed test:-

A test of any statistical hypothesis where the alternative hypothesis is one tailed test (right tailed or left tailed) is called a one tailed test.

For example, In a test for testing the mean of a population in a single tailed test.

we assume that the null hypothesis H0:μ = μ0 against the alternative hypothesis.

H1:μ > μ0 (right tailed)

H1:μ < μ0 (left tailed) is called one tailed test.

Two tailed test:-

In a test of statistical hypothesis where the alternative hypothesis is two tailed test.

we assume that the null hypothesis H0:μ = μ0

Alternative hypothesis H1 : μ ≠ μ0 is called two tailed test.

Given data

There is evidence that the mean family income in the U. S. is greater than $30,000

we will use right tailed test.

Null hypothesis : - H0:μ = μ0

Alternative hypothesis:-H1 : μ> 30,000 (right tailed test)