QUESTION IMAGE
Question
a car company says that the mean gas mileage for its luxury sedan is at least 25 miles per gallon (mpg). you believe the claim is incorrect and find that a random sample of 5 cars has a mean gas mileage of 23 mpg and a standard deviation of 2 mpg. at \\( \alpha = 0.05 \\), test the companys claim. assume the population is normally distributed. click here to view the t - distribution table. click here to view page 1 of the normal table. click here to view page 2 of the normal table. state the appropriate hypotheses to test. a. \\( h _ { 0 } : \mu \leq 25 \\) \\( h _ { a } : \mu > 25 \\) b. \\( h _ { 0 } : \mu \
eq 25 \\) \\( h _ { a } : \mu = 25 \\) c. \\( h _ { 0 } : \mu \geq 25 \\) \\( h _ { a } : \mu < 25 \\) d. \\( h _ { 0 } : \mu = 25 \\) \\( h _ { a } : \mu \
eq 25 \\) what is the value of the standardized test statistic? the standardized test statistic is \\( - 2.24 \\). (round to two decimal places as needed.) what is the critical value? the critical value is \\( - 2.132 \\). (round to three decimal places as needed.) what is the outcome and the conclusion of this test? \\( h _ { 0 } \\). at the 5% significance level, there is evidence to the car companys claim that the mean gas mileage for the luxury sedan is at least 25 miles per gallon.
Step1: Compare test statistic and critical value
We have the standardized test statistic \(t=-2.24\) and the critical value \(t_{critical}=- 2.132\). In a hypothesis test, if the test statistic falls in the rejection region (for a left - tailed test, \(t < t_{critical}\)), we reject the null hypothesis \(H_0\). Rejecting \(H_0:\mu\geq25\) means that at the \(5\%\) significance level, there is sufficient evidence to reject the car company’s claim that the mean gas mileage for the luxury sedan is at least \(25\) miles per gallon.
Since \(t=-2.24Step2: Make a decision about \(H_0\)
Step3: Interpret the result
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Reject \(H_0\). At the \(5\%\) significance level, there is sufficient evidence to reject the car company’s claim that the mean gas mileage for the luxury sedan is at least \(25\) miles per gallon.