Edit: oops someone beat me to this joke, sorry!
A physicist, an engineer, and a statistician go deer hunting. A deer walks into view and the engineer gets ready to shot. He makes some basic assumtions, supposes that the air resistance has a small enough effect to not factor into this situation, and finally fires. His bullet lands one meter short. Next, the physicist gets ready to shot. She take into account the air resistance, the effects of gravity, the curvature and rotation of the earth, and fires. Her shot lands one meter too far.
The statistician jumps up and says, "We got 'em!"