Key Concepts

• To see if changes in one variable (explanatory) causes another variable (response), experiments are used
• In an experiment, random assignment is used to assign subjects to treatments to allow researchers to focus on the variable of interest and minimize the impact of lurking variables
• Ethics related to how data is gathered and reported is crucial for making correct decisions from experiments

Glossary

blinding: not telling participants which treatment a subject is receiving

control group: a group in a randomized experiment that receives an inactive treatment but is otherwise managed exactly as the other groups

double-blinding: the act of blinding both the subjects of an experiment and the researchers who work with the subjects

experimental unit: any individual or object to be measured

explanatory variable: the independent variable in an experiment; the value controlled by researchers

informed consent: any human subject in a research study must be cognizant of any risks or costs associated with the study. The subjects have the right to know the nature of the treatments included in the study, their potential risks, and their potential benefits. Consent must be given freely by an informed, fit participant.

Institutional Review Board (IRB): a committee tasked with oversight of research programs that involve human subjects

lurking variable: a variable that has an effect on a study even though it is neither an explanatory variable nor a response variable

placebo: an inactive treatment that has no real effect on the explanatory variable

random assignment: the act of organizing experimental units into treatment groups using random methods

response variable: the dependent variable in an experiment; the value that is measured for change at the end of an experiment

treatments: different values or components of the explanatory variable applied in an experiment