Lecture Notes: Correlation and Experimental Methods

Vocabulary flashcards covering key terms from correlation and experimental methods as presented in the video notes.

Correlation

A measure of the extent to which two factors vary together, and thus of how well either predicts the other.

Correlation coefficient

A statistical index of the relationship between two things

Variable

Anything that can vary and is feasible and ethical to measure.

Scatterplot

A graphed cluster of dots representing the values of two variables; the slope suggests the direction of the relationship and the amount of scatter indicates the strength of the correlation.

Illusory correlation

Perceiving a relationship where none exists, or perceiving a stronger-than-actual relationship.

Regression toward the mean

The tendency for extreme or unusual scores or events to fall back toward the average.

Experiment

A research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variable); random assignment helps control other factors.

Experimental group

The group exposed to the treatment, i.e., to one version of the independent variable.

Control group

The group not exposed to the treatment; serves as a comparison for evaluating the effect of the treatment.

Random assignment

Assigning participants to experimental and control groups by chance, thereby minimizing preexisting differences.

Double-blind procedure

An experimental procedure in which both the participants and the research staff are ignorant about whether the participants have received the treatment or a placebo.

Independent variable

The factor that is manipulated in an experiment; the variable whose effect is being studied.

Confounding variable

A factor other than the factor being studied that might influence a study's results.

Dependent variable

The outcome that is measured; the variable that may change when the independent variable is manipulated.

Validity

The extent to which a test or experiment measures or predicts what it is supposed to.

Placebo effect

Experimental results caused by expectation alone: rather than actual treatment, where participants perceive improvements in their condition due to believing they received a treatment.