Question: Supposed Toyota Motor Corporation is studying the effect of regular versus high-octane gasoline on fuel economy of its new high-performance, 3.5 liter, V6 engine. Ten executives are selected and asked to maintain records on the number of miles traveled per gallon of gas. The results are:

At the .05 significance level, is there a difference in the number of miles traveled per gallon between regular and high-octane gasoline?