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If we can treat this data as a random sample of all models of cars produced...

If we can treat this data as a random sample of all models of cars produced in 2003, test the hypothesis that the highway mileage per gallon of automobiles exceeds 25.

n=147

mean=28.14966

standard deviation= 6.5337414

Math   Statistics-And-Probability   
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Answer #1

This is a right tail test. Since we are not given any significance level, let us assume it as 5%

As the test exceeds the critical value by a long margin, we must reject the null hypothesis and conclude that the highway mileage per gallon of automobiles exceeds 25.  In fact, a calculator shows that P-Value is < .00001.

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