Story Name: Crash Test Dummies
Story Topics: Engineering
, Health
Datafile Name: CrashTest.data
Methods: ANOVA
, ANCOVA
, Transformation
Abstract: Stock automobiles containing dummies in the driver and
front passenger seats crashed into a wall at 35 miles per hour. National
Transportation Safety Board officials collected information how the crash
affected the dummies. The injury variables describe the extent of head
injuries, chest deceleration, and left and right femur load. The datafile
also contains information on the type and safety features of each crashed
car.
One way to evaluate the relationship between car features and crash
injuries is using ANOVA with the various injury variables as dependent
variables. Histograms of the injury variables shows that all of them are
skewed right. Taking the logs of these variables results in approximately
normal distributions. You may also want to take the log of the weight variable.
The variables D/P, Protection, Doors, and Size all show significant
F-tests when included in an analysis of variance model with no interactions
and the log of head injury criterion as the dependent variable. Year and
the log of weight are not significant when included as covariates with
these variables in an analysis of covariance. However, the log of weight
is significant when the dependent variable is either left or right femur
load.
This dataset also lends itself more advanced linear models such
as MANOVA and models with various interaction terms.
Image: ANOVA table
Reference: National Transportation Safety Administration
Authorization: free use
Description: Data based on trials in which stock automobiles are crashed into a wall at 35MPH with dummies in the driver and front passenger seat.
Number of cases: 352
Variable Names:
- make: Car make
- Model: Model of that car
- carID: Usually the combination of make and model
- carID & Year: Full ID of the car
- Head_IC: Head injury criterion
- Chest_decel: Chest deceleration
- L_Leg: Left femur load
- R_Leg: Right femur load
- D/P: Whether the dummy is in the Driver or Passenger seat
- Protection: Kind of protection (seat belt, air bag, etc.)
- Doors: Number of doors on the car
- Year: Year of the car
- Wt: Weight in pounds
- Size: A categorical variable to classify the cars to a type (light, minivan)