Many drivers of cars that can run on regular gas instead buy…
Many drivers of cars that can run on regular gas instead buy premium gas in the belief that they will get better gas mileage (miles per gallon). To test that belief, a sample of 10 cars was obtained from a company fleet where all the cars can run on regular gas. Each car is filled first with either regular or premium gasoline, as decided by a coin toss, and the mileage for that full tank of gas is recorded. The mileage is again recorded for the same cars with full tank of gas of the other kind of gasoline. The car drivers were unaware that they were participating in an experiment. Research Question: Does the data suggest, on the average, that cars had a higher gas mileage (in miles per gallon) with premium gas when compared to regular gas? This is an example of paired data because there are two recorded measurements for each . On the average, 2.0 miles per gallon was achieved with premium gas. When using the paired t procedure, we successful in reducing variation between the types of gasoline, because the standard deviation for the differences: sd = miles per gallon is the standard deviations found with the original two samples for Premium and Regular gas.