A guy on a skateboard does a trick on a ramp while others watch on the other side of the ramp .
There is a better than even chance that the skateboarder fails the trick and hurts his hand .
It is impossible that the skateboarder fails the trick and hurts his hand .
There is a better than even chance that the skateboarder fails the trick and hurts his hand .
The skateboarder fails the trick and hurts his hand .