SOLUTION: Please help. In 2004, a small dealership leased 21 Chevy impalas on 2-year leases. When the cars were returned in 2006, the mileage was recorded and the 21 cars had an average

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Question 255868: Please help.
In 2004, a small dealership leased 21 Chevy impalas on 2-year leases. When the cars were returned in 2006, the mileage was recorded and the 21 cars had an average of 33,950 miles and a standard deviation of 11,866.
A) What is the null and alternate hypotheses to determine if leases exceed the national average of 30,000 miles?
B) Using alpha .10, what is the critical value for the hypothesis test?
C) What is the test statistic?
D) Make a conclusion for the hypothesis test.
Thank You!

Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
In 2004, a small dealership leased 21 Chevy impalas on 2-year leases. When the cars were returned in 2006, the mileage was recorded and the 21 cars had an average of 33,950 miles and a standard deviation of 11,866.
A) What is the null and alternate hypotheses to determine if leases exceed the national average of 30,000 miles?
Ho: u = 30,000
H1: u > 30,000
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B) Using alpha .10, what is the critical value for the hypothesis test?
Right-tail test with alpha = 10%: t = invT(0.90,20) = 1.325
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C) What is the test statistic?
t(33,950) = ((33,950-30000)/[11866/sqrt(21)] = 1.5254...
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D) Make a conclusion for the hypothesis test.
Since the test statistic is to the right of the critical value reject Ho.
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Cheers,
Stan H.

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