. A manufacturer of a new car claims the typical car will average 33 mpg of gasoline. An independent consumer group is skeptical of the claim and thinks the mean gas mileage is significantly different than the 33 claimed. A sample of 50 randomly selected cars produced a mean mpg of 31 with a standard deviation of 3.5. Assume that cars’ gas mileage is normally distributed in the population. ). a. The manufactures want to determine if the mean mpg for the cars is significantly different from 33. Write the null and alternative hypotheses for this question. b. What are the assumptions of this test? Are the assumptions met? ). C. Calculate and interpret the 95% confidence interval, and assess whether to reject the null hypothesis based on the interval. Use a t critical of 2.01.
. A manufacturer of a new car claims the typical car will average 33 mpg of gasoline. An independent consumer group is skeptical of the claim and thinks the mean gas mileage is significantly different than the 33 claimed. A sample of 50 randomly selected cars produced a mean mpg of 31 with a standard deviation of 3.5. Assume that cars’ gas mileage is normally distributed in the population. ). a. The manufactures want to determine if the mean mpg for the cars is significantly different from 33. Write the null and alternative hypotheses for this question. b. What are the assumptions of this test? Are the assumptions met? ). C. Calculate and interpret the 95% confidence interval, and assess whether to reject the null hypothesis based on the interval. Use a t critical of 2.01.
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