RM10 Experiments

What is a confound?

a variable that systematically varies with the IV

What is an example of a confound?

each IV group had a different therapist with the different treatements

• could have different scores due to therapists

What is Between-Subjects IV?

Each subject participates in only one level of the IV

What is Within-Subjects IV?

Each subject participates in every level of IV

What are the two common kinds of Between-Subjects tests?

Posttest-only design and Pretest-posttest design

What is a posttest-only design?

the dependent variable are the scores after a test

• each group gets a different studying method

• can’t measure the variable multiple times, only once

What is a pretest-posttest design?

The DV is the posttest score-pretest score

• each group get a different studying method

• a different version of the exam is administered before and after to find improvement

what is the order effect?

the exposure to one level of testing affects the score on the next level or levels

What are examples of the order effect?

• scores improve over test trials because of practice

• scores worsen over trial due to boredom or fatigue

What is the solution to order effect?

counterbalancing

what is counterbalancing?

in different research groups, vary the order of levels so order effect cancels out

What is linear regression?

How does one thing affect a variable?

What is multiple regression?

How do multiple things affect a variable?

What are demand characteristics?

cues in a research study that give participants a hint about the purpose of the study or how theyre expected to behave

How can within-subject tests be affected by demand characteristics?

with subjects partaking in every level, it is easier to infer the hypothesis of the study

What are some advantages of Within-Subjects tests?

• the researchers can ask which strategy they prefered

• takes less people total

What is Cohens d?

a way of measuring effect size

• depends on means and variance