In 1990, the mean 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 mean duration of long-distance phone calls has changed from the 1990 mean of 7.2 minutes. H0: μ < 7.2 minutes Ha: μ > 7.2 minutes H0: μ = 7.2 minutes Ha: μ ≠ 7.2 minutes H0: μ = 7.2 minutes Ha: μ ≤ 7.2 minutes H0: μ ≠ 7.2 minutes Ha: μ = 7.2 minutes