20 points
Data from a certain village hospital show that the number of frostbite cases is positively correlated with the number of sledding accidents. Which of the following factors would
best explain why this correlation does not necessarily imply that frostbite is the main cause of sledding accidents?
People with frostbite tend to have more difficulty controlling sleds.
the frostbite cases and sledding accidents were not randomly selected.
The hospital treats more sledding accidents than cases of frostbite.
It is likely that both the number of frostbite cases and the number of sledding accidents are negatively correlated with temperature.