Split a database between a small car engine the ignition by sparks and small cars that use the engine, the ignition with a soft. To sort out a number of independent testing, split according to the type of the car:
Separate databases between small cars that use spark ignition engines with smaller cars and used with compression ignition engines. The numbers separated by independent testing by the type of the car.
Separate database between a small car with positive ignition engines, cars and small engines ignition by compression. The number of separate independent test sort by vehicle type, as follows: