Experiments help researchers determine whether changing one variable causes a change in another. Careful design is essential: without it, differences between groups may be caused by factors other than the treatment being studied.
An experiment investigates the relationship between variables. The explanatory variable is the variable the researcher changes or uses to explain an outcome. The response variable is the outcome measured to determine whether it changes.
All flashcards
What are the explanatory and response variables?
The explanatory variable is the factor used to explain an outcome or manipulated by the researcher. The response variable is the outcome measured.
What is a lurking variable?
A lurking variable is an additional factor that may affect the response and obscure or distort the relationship being studied.
What is random assignment, and why is it useful?
Random assignment uses chance to place experimental units into treatment groups. It tends to spread potential lurking variables across groups and helps make a fair treatment comparison.
What roles do a control group and a placebo play?
A control group provides a comparison condition. A placebo resembles an active treatment but cannot directly affect the response, helping researchers account for expectations and the experience of participating.
What makes an experiment double-blind?
Both the participants and the researchers who interact with them do not know which participants are receiving the active treatment.
Quiz questions
What is an experimental unit in an experiment?Answer: The individual or object that receives a treatment and is measured.
Why can comparing vitamin E users with nonusers fail to show that vitamin E improves health?Answer: The groups may differ in other health-related factors, such as diet or exercise, that affect the outcome.
What is the purpose of a control group in an experiment?Answer: It provides a comparison condition for separating treatment effects from study participation or expectations.
What is a placebo in an experiment?Answer: A treatment designed to resemble the active treatment but not directly affect the response.
In a double-blind medication experiment, who is unaware of treatment assignments?Answer: Both the participants and the researchers who interact with them.
Based on Introductory Statistics 2e by Barbara Illowsky, Susan Dean (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.