A car company says that the mean gas mileage for its luxury sedan is at least 21
ID: 3252437 • Letter: A
Question
A car company says that the mean gas mileage for its luxury sedan is at least 21 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 19 mpg and a standard deviation of 3 mpg. At a *0.10, 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. which sampling distribution should betsed and why? O A. Use a normal sampling distribution because the population is O B. Use a t-sampling distribution because the population is normal, and normal, and o is unknown. a is known. O C. Use a normal sampling distribution because n 30. O D. Use a t-sampling distribution because nExplanation / Answer
Which sampling distribution should be used and why?
F. Use a t-sampling distribution because the population is normal and s is unknown.
State the appropriate hypothesis to test:
A. Ho: µ 21
Ha: µ < 21
What is the appropriate hypothesis to test:
t = (x bar - µ)/(s/sqrt(n))
= (19 -21)/(3/sqrt(5))
= -1.49
The standardized test statistics is -1.49
What is the critical value?
The critical value is -1.533
What is the outcome and conclusion of the test?
Fail to reject the null hypothesis and at 10% level of significance there is sufficient evidence to conclude that the mean gas mileage for its luxury sedan is at least 21 miles per gallon (mpg).