11.24 In a bumper test, three types of autos were deliberately crashed into a barrier at 5 mph, and the resulting damage (in dollars) was estimated. Five test vehicles of each type were crashed, with the results shown below. Research questions: (a) What is the null hypothesis being tested? (b) At the .05 significance level, are the mean crash damages the same or significantly different among these three vehicles? (c) Explain your decision using the critical value or p value method.