Experimental Design

The parts of the experiment that must be kept the same.

• Controls

• Treatments

• Blocking

A researcher randomly assigned students to two groups. One group was assigned to watch a violent television program while the other group watched a nonviolent program. The student's behavior was then recorded for incidences of aggressive behavior. Which research method is most appropriate?

• experimental

• Prospective Study

• Retrospective Study

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?

• experiment

• observational study

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?

• Experiment

• Observational study

• Neither

• Both experiment and observational study.

State whether the situation represents an experimental study or an observational study.

Suppose you are trying to determine if a vaccine is effective against an infectious disease such as COVID-19 in those 65 years and older. Each participant will receive one of two treatments - either the vaccine or a placebo. Randomly assign 1000 participants into 500 matched pairs. Each pair is matched on gender and age. The first pair might be men, both age 72, the second pair might be women aged 70 and so on.

• Observational study

• Experimental study

Answer explanation

This is an experimental study. The treatment group receives the vaccine while the control group receives the placebo.

Thankfully, I don't have COVID, but I did break my paw.:(

State whether the situation represents an experimental study or an observational study.

Suppose you are trying to determine how much RTA is used by Tri-C students. Find 100 Tri-C students who work full time and 100 Tri-C students who do not work at all. Compare their grade point averages.

• Observational study

• Experimental study

Answer explanation

This is observational since the groups being compared have no treatment applied. Observations are made about recorded data.

I'm glad I don't have to work. It is hard being a dog though!

State whether the situation represents an experimental study or an observational study.

Suppose you want to find out if people who drink a mix of creatine, BCAAs and caffeine before a workout, perform better during their session. Randomly divide the participants into 2 groups. One group will drink the mix 30 minutes before the workout and the other group will not. Their results will be compared.

• Observational study

• Experimental study

Answer explanation

The treatment group received the drink mix and the control group did not. Since the participants were randomly assigned and a treatment (drink mix) was given, this is an experimental study.

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

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

• experiment

• observational study

Why is the placebo effect used?

• To compare results between the real medicine and placebo

• To make new medicine

• To train doctors

• To make food