From Past Records It Is Known That the Average Life

question 6

Multiple Choice

From past records it is known that the average life of a battery used in a digital clock is 305 days.
The battery life is normally distributed. The battery was recently modified to last longer. A sample of
20 of the modified batteries was tested. It was discovered that the mean life was 311 days and the
Sample standard deviation was 12 days. We want to test at the 0.05 level of significance whether
The modification increases the life of the battery. What is our decision rule?

• A) Do not reject the null hypothesis if computed t is 1.96 or greater
• B) Reject the null hypothesis if computed t is less than 1.96
• C) Do not reject the null hypothesis if computed t is 1.729 or greater
• D) Reject the null hypothesis if computed t is 2.086 or greater
• E) Reject the null hypothesis if the computed t is 1.729 or greater

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Definitions:

Direct Labor Rate

The cost per hour for labor directly involved in manufacturing a product or providing a service.

Machine Hours

A measure of production output or activity level, using the total hours that machinery is operated as the unit of measure.

Machine Hours

The total running time of a machine during a specific period, often used as a basis for allocating manufacturing overhead.

Annual Overhead Costs

The total expenses related to the operation of a business that are not directly tied to a specific product or service, accumulated yearly.