The average mpg usage for a 2009 Toyota Prius for a sample of 10 tanks of gas was 45.5 with a standard deviation of 1.8. For a 2009 Honda Insight, the average mpg usage for a sample of 10 tanks of gas was 42.0 with a standard deviation of 2.3.
(a) Assuming equal variances, at α = .01, is the true mean mpg lower for the Honda Insight?
(b) Calculate the p-value using Excel.