In 1990, the Average Duration of Long-Distance Telephone Calls Originating $\mathrm{H}_{0}: \mu=9.3$

question 57

Multiple Choice

In 1990, the average duration of long-distance telephone calls originating in one town was 9.3 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 9.3 minutes.
Formulate the null and alternative hypotheses for the study described.

• A) \( \mathrm{H}_{0}: \mu=9.3 \) minutes
• \( \mathrm{H}_{\alpha}: \mu<9.3 \) minutes
• B) \( \mathrm{H}_{0}: \mu=9.3 \) minutes
• \( \mathrm{H}_{\alpha}: \mu>9.3 \) minutes
• C) \( \mathrm{H}_{0}: \mu=9.3 \) minutes
• \( \mathrm{H}_{\alpha}: \mu \neq 9.3 \) minutes
• D) \( \mathrm{H}_{0}: \mu \neq 9.3 \) minutes
• \( \mathrm{H}_{\alpha}: \mu=9.3 \) minutes

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