A physicist, engineer and a statistician are out hunting. They spot a deer, in the long grass, maybe 300 yards away.

The physicist conducts some fundamental ballistic calculations in his head, assuming a vacuum, lifts his rifle to the angle he has worked out, and shoots. The bullet lands 5 yards short.

The engineer adds a fudge factor for air resistance, lifts his rifle slightly higher, and shoots. The bullet lands 5 yards long.

The statistician yells “We got him!”