A major oil company has developed a new gasoline additive thatis supposed to increase mileage. To test this hypothesis, ten carsare randomly selected. The cars are driven both with and withoutthe additive. The results are displayed in the following table. Canit be concluded, from the data, that the gasoline additive doessignificantly increase mileage?
Let d=(gas mileage with additive)?(gas mileage withoutadditive). Use a significance level of ?=0.05 for the test. Assumethat the gas mileages are normally distributed for the populationof all cars both with and without the additive.
| Car | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| W/O Additive | 22.1 | 9.3 | 24.9 | 25.2 | 19.4 | 26.5 | 18.7 | 22.4 | 12.3 | 22.1 |
| W/ Additive | 25.1 | 11.6 | 26.6 | 28.5 | 21.4 | 28.7 | 19.5 | 25.6 | 14.6 | 24.5 |
Step 1 of 5: State the null and alternative hypotheses for thetest.
Step 2 of 5: Find the value of the standard deviation of thepaired differences. Round your answer to two decimal places.
Step 3 of 5: Compute the value of the test statistic. Round youranswer to three decimal places
Step 4 of 5: Determine the decision rule for rejecting the nullhypothesis H0H0. Round the numerical portion of your answer tothree decimal places.
Step 5 of 5: Make the decision for the hypothesis test.
