Question

Regarding: smoking tobacco cigarettes and lung cancer

These two events--"smoking" and "lung cancer"--are strongly correlated, and clinical trials have been conducted to show that smoking is a contributing factor to the development of lung cancer.

Which statement best reflects the relationship between smoking tobacco cigarettes and lung cancer?

The relationship is correlated but not causal because lung cancer doesn't cause smoking--the causality only goes one way.

The relationship is correlated and causal: smoking causes lung cancer.

The relationship is correlated but not causal because you can smoke and not get lung cancer.

The relationship is correlated but not causal because you can get lung cancer even if you never smoked.

Answer 1

It is given that:

The two events "smoking" and "lung cancer" are strongly correlated. Also, clinical studies shows that smoking is a contributing factor to the development of lung cancer. This suggests that trials have proved that exposure to smoking increases the risk of cancer.

This rules out option 1, 3 and 4. The options 3 and 4 does make sence, but the probability of developing a lung cancer is higher for those who smoke and hence, it may be said that smoking (though not the only cause), causes cancer.

The correct option would be:

The relationship is correlated and causal: smoking causes lung cancer.