Question

A study conducted in year 2002 found that the mean number of children under 18 per household in a certain community was 1.7. A statistician is trying to determine whether this number has changed in the last 6 years. She declares the null and alternative hypotheses to be: Null: The mean number of children per household in 2002 is equal to 1.7; Alternative: The mean number of children per household in 2002 is not equal to 1.7. Which of the following statements is true about this test?

a. This is a step-tailed test.
b. This is a left-tailed test.
c. This is a two-tailed test.
d. This is a right-tailed test.

Answer 1

c. This is a two-tailed test.

Explanation:

When the rejection region is divided between the two tails of the sampling distribution of the test statistic the test is referred to as two tailed or two sided test. In this case the alternative is set up as

Ha : u≠ 1.7

meaning that values both larger and smaller than u are to be included.

When the alternative hypothesis has the "not equal to sign" it gives the two tailed test.