A man carrying a backpack on his back walks in a large field of grass .
Chances are about even that the man is carrying a backpack as he walks across the field to school .
Chances are about even that the man is carrying a backpack as he walks across the field to school .
It is highly unlikely that the man is carrying a backpack as he walks across the field to school .
The man is carrying a backpack as he walks across the field to school .