Fuel Economy, Minivans ~ The Environmental Protection Agency (EPA) publishes fuel economy values that are known to be good estimates of the fuel economy a typical driver will achieve under average driving conditions. One of the fuel economy values the EPA publishes is a combined estimate, which represents a combination of city driving (55%) and highway driving (45%).Toyota Sienna, a popular minivan, advertises an average combined fuel usage of 22 mpg. A large rental company collected the information about combined fuel economy (mpg) for their 10 Toyota Sienna minivans. The results are shown in the table below.

22.8

22

20.4

22.3

21.4

21.4

19.3

22.3

21.9

21.5

The company calculates the sample mean to be 21.53 and sample standard deviation as 1.0242.Round all calculated values to 4 decimal places as appropriate.1. The management believes that Toyota has overestimated the fuel economy of the Sienna. Which set of hypotheses should we use to determine if the fuel efficiency of the Sienna is less than what is advertised?A. H0:=22H0:=22 vs. Ha:>22Ha:>22 B. H0:=22H0:=22 vs. Ha:<22Ha:<22 C. H0:<21.53H0:<21.53 vs. Ha:>21.53Ha:>21.53 D. H0:=22H0:=22 vs. Ha:22Ha:22

2. What conditions must be met if we want to perform a hypothesis test and answer the question of the management? Select all that apply: A. Population data must be nearly normal or the sample size must be at least 30. B. There must be at least 3 levels of the categorical variable. C. np^10andn(1p^)10np^10andn(1p^)10 D. The observations are independent.

3. Assuming the conditions for the hypothesis test are met, find the test statistic and the p-value.test statistic = p-value =

4. Find and interpret the effect size for this study.Here d^=d^= and we have a ? small small to moderate moderate to large large effect size.

5. A competing rental car company has two large fleets, one in Michigan and one in Ohio. They instruct managers in each state to conduct a similar test for the Toyota Sienna minivans in their fleet.The manager in Michigan tests 24 minivans and obtains a p-value of 0.119 and an effect size of 0.57.The manager in Ohio tests 67 minivans and obtains a p-value of 0.0023 and an effect size of 0.6.The results in Ohio ? confirm conflict with the results in Michigan because the ? p-values effect sizes sample sizes are ? similar dissimilar .