To test whether a fuel additive improves gas mileage, investigators measured the gas mileage (in miles per gallon) of nine cars with and without the fuel additive. At a level of α = 0.10, can it be concluded that the additive improved gas mileage ? The results are shown below.
Car 1 2 3 4 5 6 7 8 9
Gas mileage without additive
34.5 36.7 34.4 39.8 33.6 35.4 38.4 35.3 37.9
Gas mileage with fuel additive 36.4 38.8 36.1 40.1 34.7 38.3 40.2 37.2 38.7
Identify the claim and Ho & Ha for this investigation.
Which one is the critical value to for this problem?
What is the value of d(bar)?
What is the value of sd?
If we use t-test, what will be the standardized test statistic t?
This solution conducts a hypothesis test to determine whether a fuel additive will improve gas mileage.