I am testing gas mileage between three brands of gasoline. I am testing on a small population of 10 cars.
Hypothesis: Cars using higher grade gasoline will have a significant higher gas mileage than cars using regular grade gasoline.
Null Hypothesis: There will be no significant difference in gas mileage between cars using regular grade gasoline and higher grade gasoline.
The cars first fill up with regular gasoline and record the mileage. Then they fill up with super gasoline and record the mileage. Lastly, they fill up with ultra gasoline and record the mileage.
I am doing tests between:
- Regular and super
- Regular and ultra
- Super and ultra
I am not sure of which test I should use on my data. I was thinking maybe Levene's test or an independent t-test, but I'm not sure.
Any thought about this?