In 2013,the average duration of long-distance telephone calls originating in one town was $7.2 \text { minutes. }$ A long-distance telephone company wants to perform a hypothesis test to determine whether the average duration of long-distance phone calls has changed from the 2013 mean of $7.2 \text { minutes. }$

Question

Quizplus · Accepted Answer

The two-sided test is the best choice for this scenario because the question is asking whether the average duration of long-distance phone calls has changed from the 2013 average. There is no prior assumption or expectation of the direction of the change. Therefore, both the possibility of the mean being lower or higher than the 2013 average should be considered. A two-sided test will test for the possibility of a significant difference in either direction, making it the best choice here.

In 2013,the Average Duration of Long-Distance Telephone Calls Originating in One