Experimental versus Observational Study

One group of subjects was given an herbal supplement and another group was given a placebo. After one year, the number of illnesses each group had was compared.

• Observational Study

• Experiment

A researcher stood at a school parking lot entrance to see if the color of a car is related to the driver not wearing a seatbelt.

• Observational Study

• Experiment

A professor finds that people who are obese have higher cholesterol levels than those who are not obese.

• Observational Study

• Experiment

Four groups of randomly selected people are assigned a different diet. After six months, the blood pressures of each group are compared.

• Observational Study

• Experiment

You want to see if students who have a 4.0 grade point average study more than those who do not.

• experiment

• observational study

You want to compare the health of students who walk to school to the health of students who ride the bus

• experiment

• observational study

A researcher randomly assigned boys and girls to each of two groups. One group was assigned to watch a violent television program while the other group watched a nonviolent program. The children's behavior was then recorded for incidences of aggressive behavior. This research method is best characterized as...

• experimental

• Observation

A psychologist designed a study to test the effects of cell phone use on driving safety. Participants were randomly assigned either to drive an automobile simulator while talking to a friend on a cell phone or to drive a simulator without talking on a phone.

Which type of research does the scenario describe?

• Experiment

• Observation

To test the effects of breakfast on grades I ask my students if they ate breakfast and then compare the breakfast eaters grades to the non-breakfast eaters.

This is an example of:

• Observational study

• Experiment

Researchers wanted to know if there is a link between proximity to high-tension wires and the rate of leukemia in children. To conduct the study, researchers compared the rate of leukemia for children who lived within 1/2 mile of high-tension wires to the rate of leukemia for children who did not live within 1/2 mile of high-tension wires.

• Observational Study

• Experiment