EPIDEMIOLOGY UNIT 2 STUDY GUIDE

Runners after an ultramarathon commonly develop respiratory infections. We want to know if taking 600 milligrams of vitamin C daily will reduce these infections. Researchers randomly assigned 100 ultramarathon runners to receive either vitamin C or placebo. All subjects were watched for 14 days after the big race to see if infections developed. What are the possible lurking variables?

• Age of the runner
• weight of the runner
• gender of the runner
• all of the above

The most important advantage of experiments over observational studies is that

• A) experiments are usually easier to carry out
• B)Experiments can usually give better evidence of causation
• C) Confounding cannot happen in experiments
• D) Observational studies cannot use random samples

An organized way to collect and record scientific observations is with a(n)

• model.

• inference.

• data table.

• operational definition.

During an experiment, which factors must be controlled so that researchers can draw a logical conclusion from the experiment?

• variables

• operational definitions

• inquiries

• theories

In a scientific experiment, the responding variable can also be called the

• operational variable

• manipulated variable

• dependent variable

• independent variable

A possible explanation for a set of observations or answer to a scientific question is called a(n)

• predictions.

• hypothesis.

• theory.

• law.

Which of the following are NOT examples of data?

• quantitative observations

• qualitative observations

• theories

• measurements

One useful tool that may help a scientist interpret data by revealing unexpected patterns is a

• variable.

• graph.

• theory.

• law.

Using one or more of your senses to gather information is called

• observing.

• inferring.

• predicting.

• classifying.

A summary of what you have learned from a scientific experiment is called a(n)

• hypothesis.

• inquiry.

• conclusion.

• law.