Suppose the National Transportation Safety Board (NTSB) wants to examine the safety of compact cars, midsize cars, and full-size cars. It collects a sample of three for each of the car types. Each car...

Suppose the National Transportation Safety Board (NTSB) wants to examine the safety of compact cars, midsize cars, and full-size cars. It collects a sample of three for each of the car types. Each car in the sample is subjected to a crash test, and the mean pressure applied to the driver's head is measured. Data is stored in fileCrashTest. NTSB wants to test whether the mean pressure applied to the driver’s head during a crash test is equal for each type of car.