For decades, researchers, politicians, and tobacco company executives debated the relation between smoking and health problems such as cancer.

a. Why was this research necessarily correlational in nature?

b. What confounding variables might make it difficult to isolate the health effects of smoking tobacco?

c. How might the nature of this research and these confounds buy time for the tobacco industry with regard to acknowledging the hazardous effects of smoking?

d. All ethics aside, how could you study the relation between smoking and health problems using a between-groups experiment?