Question

# A highway safety institution conducts experiments in which cars are crashed into a fixed barrier at...

A highway safety institution conducts experiments in which cars are crashed into a fixed barrier at 40 mph. In the​ institute's 40-mph offset​ test, 40% of the total width of each vehicle strikes a barrier on the​ driver's side. The​ barrier's deformable face is made of aluminum​ honeycomb, which makes the forces in the test similar to those involved in a frontal offset crash between two vehicles of the same​ weight, each going just less than 40 mph. You are in the market to buy a family car and you want to know if the mean head injury resulting from this offset crash is the same for large family​ cars, passenger​ vans, and midsize utility vehicles​ (SUVs). The data in the accompanying table were collected from the​ institute's study.

 Large_Family_Cars Passenger_Vans Midsize_Utility_Vehicles 265 147 226 134 238 214 407 343 186 528 698 309 149 548 354 625 473 551 167 323 397

a.) Normal probability plots indicate that the sample data come from normal populations. Are the requirements to use the​ one-way ANOVA procedure​ satisfied?

b.) Test the null hypothesis that the mean head injury for each vehicle type is the same at the α=0.01 level of significance.

c.) What is the P-value ​(Round to four decimal places as​ needed.)

Determine the​ P-value and state the appropriate conclusion below.

Since the​ P-value is _______ there is sufficient / insufficient evidence to accept / reject the null hypothesis.​ Thus, we can / cannot conclude that the means are different at the α = 0.01level of significance.

​(Round to four decimal places as​ needed.)

d.) Draw box plots representing the data