Help with a psychology problem?

This question was given in psychology and I keep getting confused on what the dependent and independent variables would be because i keep over thinking the problem. Problem below--%26gt;





There is a strong positive correlation between cigarette smoking and cancer. The tobacco industry makes a big deal out of the fact that no true causal link between smoking and cancer has been established in humans ( all cause and effect studies have been performed on animals). They are right because the research on humans has been correlation in nature.





What is the independent variable?


What is the dependent variable?





I believe the independent variable would be the smoking of cigarettes while cancer is the dependence?


Tell me what you think it is and offer explanation for your reason ? Thank You =]|||You're right.





An independent variable is a variable that can exist on its own. (smoking)





A dependent variable is a variable that requires another variable be defined. (increase in cancer risk)





The dependent variable ("cancer risk") stays the same in the population until you add the variable of smoking, which has a positive correlation. That is, as the independent variable goes up (how many people smoke), so does the dependent (how many people have cancer).





I'm actually surprised this is a psychology question, it seems like more of a statistics question.