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

question 14

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.

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Definitions:

Duplicate Programming

The practice of unnecessarily repeating code or functionality within a software application, which can lead to inefficiency.

Machine Cycle

The basic operation cycle of a computer's CPU, typically involving fetching an instruction from memory, decoding it, and then executing it.

Processor Scan

The cyclical process by which a programmable logic controller reads inputs, executes logic, and updates outputs.

RET Instruction

A command in programming used to return from a subroutine or function, often restoring the state at the point of the call.