Vapor or electronic cigarettes have increased dramatically over the past five years. Compared to traditional tobacco products a lot of research has not been performed on alternative smoking devices even though the sales of these devices have double and then tripled. One study conducted at Virginia Commonwealth University considered the following factors: carbon monoxide concentration, heart rate, subjective effects of the user, and plasma nicotine concentration. The study consisted of 32 subjects. The subjects came from four separate groups, traditional cigarettes, 18-mg nicotine cartridge vapor brand, 16-mg nicotine cartridge vapor brand, and a device containing no vapors. After five minutes of smoking, the smokers of the traditional cigarettes saw increased levels of carbon monoxide, heart rate, and plasma nicotine. The electronic vapor cigarette smokers did not see a significant increase in heart rate or subjective effects to the user. 

Answer the following questions.
1. What type of study was this (observational, quasi-experimental, or experimental)?
2. What are the independent and dependent variables?
3. Which was the treatment group?
4. Could the subjects’ blood pressures be affected by knowing that they are part of a study?
5. List some possible confounding variables.
6. Do you think this is a good way to study the effect of smokeless tobacco?