Just a Pinch Between Your Cheek and Gum As the evidence on the adverse effects of cigarette smoke grew, people tried many different
ways to quit smoking. Some people tried chewing tobacco or, as it was called, smokeless
tobacco. A small amount of tobacco was placed between the cheek and gum. Certain
chemicals from the tobacco were absorbed into the bloodstream and gave the sensation of
smoking cigarettes. This prompted studies on the adverse effects of smokeless tobacco.
One study in particular used 40 university students as subjects. Twenty were given smokeless
tobacco to chew, and twenty given a substance that looked and tasted like smokeless tobacco,
but did not contain any of the harmful substances. The students were randomly assigned to
one of the groups. The students' blood pressure and heart rate were measured before they
started chewing and 20 minutes after they had been chewing. A significant increase in heart
rate occurred in the group that chewed the smokeless tobacco. 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 students' 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?