Chapter 2

In vitro

"Test tube" experimenting on parts derived from living organism, such as cells.

Placebo

A fake treatment, such as a sham pill, injection, or medical procedure.

Experiment

A systematic way of testing a hypothesis.

Control group

Does not receive treatment; human subjects may receive a placebo.

Case-control study

Individuals who have a health condition are compared with individuals with similar characteristics who do not have the condition.

Experimental epidemiological studies

Obtain information about health conditions that may have resulted from specific dietary practices.

Variable

Personal characteristic or other factor that changes and can influence an outcome.

Hypothesis

Possible explanation about an observation that guides scientific research.

Treatment group

Receives treatment.

Anecdote

Reports of personal experiences.

Cohort study

Study that measures variables in a group of people over time.

In vivo

Testing on whole living organisms, such as lab rodents.

What Is the Placebo Effect?

The placebo effect occurs when a person reports a positive (or negative) reaction to a treatment even though he or she received the placebo.

Epidemiology

The study of occurrence, distribution, and causes of health problems in populations.