In 1990,the average duration of long-distance telephone calls originating in one town was 7.2 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 1990 mean of 7.2 minutes.

Question

Quizplus · Accepted Answer

A two-sided test is appropriate because we want to determine whether the average duration of long-distance phone calls has changed from the 1990 mean of 7.2 minutes, but we do not have a specific direction in mind.

In 1990,the Average Duration of Long-Distance Telephone Calls Originating in One