Dr. Larson was interested in whether classical music helps students perform better on a test. Dr. Larson randomly assigned half of the study's participants to a group that listened to classical music while taking a test. The other half of the participants did not listen to music while taking a test. Which research method is most appropriate?

Jane Goodall lived among wild chimpanzees intermittently for decades, studying their social and family systems while keeping her interaction with the chimpanzees to a minimum. Which research method is most appropriate?

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?

To test the effects of eating breakfast on test grades. I randomly select half of my students and feed them breakfast while giving the other half nothing to eat. I then give them all a test and compare the test grades of each group.

Is this an experiment or an observational study?

A hospital wants to open a gym. They ask the night-shift ER staff when they would use the gym. Is this sample biased or unbiased?

Ghala wanted to know what the most popular book was in the whole school, so she asked everybody in 11th grade what their favorite book was. Which research method is most appropriate?

Osman wanted to know what this weekends favorite movie was among RBHS students so he asked everyone at RBHS and counted the number of movie preferences.

Which research method is most appropriate?

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 seat belt.

Which research method is most appropriate?

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

Which research method is most appropriate?