Using examples from everyday life, explain why a correlation between two variables does not prove a cause and effect relation between the variables

Question

What will be an ideal response?

Answer 1

A good answer will be similar to the following:
There is a positive correlation between the number of fire trucks at a fire and the number of deaths in the fire. In other words, the more fire trucks at a fire, the more people who will die in the fire. However, it doesn't make sense to say that the fire trucks cause the deaths or that the number of deaths caused the presence of more fire trucks. In this case, a third variable, the size of the fire, leads to more fire trucks at the fire and the likelihood of more deaths in the fire. So, while the number of fire trucks and the number of deaths are correlated there is no cause-effect relation between the two variables. (Note: Student's examples will vary, but the logic should be similar to the logic given in this example.)