As the use of e-cigarettes, or vaping, becomes more popular, researchers are exploring the potential negative effects from this behavior. According to Scientific American (2018), researchers have investigated the harmful effects of nicotine, including its links to heart disease, as well as the dangers of several carcinogens inhaled while vaping.

a. Why was this research necessarily correlational in nature?

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

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

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