In 1990 , the Average Duration of Long-Distance Telephone Calls $9.4$

Multiple Choice

In 1990 , the average duration of long-distance telephone calls originating in one town was $9.4$ 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 $9.4$ minutes. The mean duration for a random sample of 50 calls originating in the town was $8.6$ minutes. Does the data provide sufficient evidence to conclude that the mean call duration, $\mu$ , has changed from the 1990 mean of $9.4$ minutes? Perform the appropriate hypothesis test using a significance level of $0.01$ . Assume that $\sigma=4.2$ minutes.

A) Since the P-value is greater than the significance level, the data provide sufficient evidence to accept the null hypothesis and conclude that the mean call duration has changed.
B) Since the P-value is less than the significance level, the data provide sufficient evidence to reject the null hypothesis and conclude that the mean call duration has changed.
C) Since the P-value is greater than the significance level, the data provide insufficient evidence to reject the null hypothesis and conclude that the mean call duration has changed.
D) Since the P-value is greater than the significance level, the data provide sufficient evidence to reject the null hypothesis and conclude that the mean call duration has changed.