1. A company with a large fleet of cars hopes to keep gasoline costs down and sets a goal of attaining a fleet average of at least 26 miles per gallon. To see if the goal is being met, they check the gasoline usage for 50 company trips chosen at random, finding a mean of 25.02 mph, and a standard deviation of 4.23 mph.

a. For a 94% level of confidence what is the appropriate critical value t* that needs to be used to calculate the margin of error? Determine the value of the critical value using a table or preferred technological tool. Show the degrees of freedom to receive full credit.

b. What is the margin of error for a 94% confidence interval for the mean for fuel efficiency?

c. Construct a 94% confidence interval for the population mean fuel efficiency.

d. Explain what the 94% confidence interval represents.

e. Based on the confidence interval is the company meeting their fleet fuel efficiency standards? Explain.

2. A tire manufactured is considering a newly designed thread pattern of its all-weather tires. Tests have indicated that these tires will provide better gas mileage and longer tread life. One of

the tests conducted is for braking effectiveness. The company hopes that the tire will allow care traveling at 60 mph to come to a complete stop within an average of 125 ft after the brakes are applied. They will adopt the new thread pattern unless there is strong evidence

that the tires do not meet this objective. The distance in feet for 10 stops on a test track was 129, 128, 130, 132, 135, 123, 102, 125, 128, and 130.

a. State the hypotheses to be tested

b. What type of test is this: one-sided (left tailed), one-sided (right-tailed), or two-sided?

c. Compute the value of the test statistic (the t-value).

d. Compute the P-value. Include the details of your calculation or calculator commands.