Exhibit: Tires Life Expectancy.

A tire manufacturer has been producing tires with an average life expectancy of 25,000 miles. Now the company is advertising that its new tires' life expectancy has increased. In order to test the legitimacy of the advertising campaign, an independent testing agency tested a sample of 6 of their tires and has provided the following data.

Life Expectancy

(In Thousands of Miles)

28

27

25

28

29

25

Answer the following questions rounding your solutions to4 digits.

Question 34

Refer to the Exhibit Tires Life Expectancy.

Determine the standard deviation of life expectancy for the sample of tires.

Question 35

Refer to the Exhibit Tires Life Expectancy.

Provide the null and the alternative hypotheses.

Question 36

Refer to the Exhibit Tires Life Expectancy.

Compute the test statistic.

Question 37

Refer to the Exhibit Tires Life Expectancy.

Compute thep-value for the test.

Question 38

Refer to the Exhibit Tires Life Expectancy.

State your conclusion for the test using thep-value.

p-value < 0.03, so we do not reject Ho. Therefore, there is enough evidence to conclude that the mean life expectancy of the new tires has decreased.

p-value < 0.03, so we reject Ho. Therefore, there is enough evidence to conclude that the mean life expectancy of the new tires has increased.

p-value < 0.03, so we reject Ho. Therefore, there is enough evidence to conclude that the mean life expectancy of the new tires has decreased.

p-value < 0.03, so we do not reject Ho. Therefore, there is not enough evidence to conclude that the mean life expectancy of the new tires has increased.

Question 39

Refer to the Exhibit Tires Life Expectancy.

Do we need any additional assumptions about the life expectancy of the tires in the population to make sure that the conclusion stated in the previous question is reliable?

No. Using the information in the problem, we can calculate the test statistic and thep-value. So, everything is provided to conduct the test and obtain the conclusions without any additional information or any additional assumptions.

Yes. The life expectancy of the tires should follow the normal distribution in the population which would guarantee that the conclusions derived in the test are reliable.

No. The sample standard deviation can be calculated based on the given information, which guarantees that the conclusions derived in the test are reliable.

Yes. The population standard deviation of the life expectancy of the tires should be known to obtain reliable conclusions.