In a correlational study, X is the number of hours of violent television programs that participants watch, and Y is the number of violent acts committed by the participants in real life. Suppose that there is a moderately high correlation (say, .48) between X and Y for a sample of 100 American males and that this result is statistically significant. Explain why we cannot infer causation from a correlational study by showing that each of the following is possible:

(a) X could cause Y.

(b) Y could cause X.

(c) The relationship between X and Y could be caused by a third variable. (Consider physiological causes of violent behavior.)