PSYCH109 Important Definition's - DOUG

Independent Variable (IV)

Variable manipulated by the researcher.

Dependent Variable (DV)

Variable measured by the researcher.

Reliability

Consistency of a measure. Produces similar results when repeated.

Validity

Whether a measure actually measures what it is intended to measure.

Correlation

A relationship between two variables.

Causation

One variable directly causes changes in another variable.

Third Variable Problem

A separate variable may explain why two variables are correlated.

Confounding Variable

Any variable other than the independent variable that could influence the dependent variable.

Observational (Correlational) Design

Measures variables without manipulating them. Can identify relationships but cannot prove causation.

Experimental Design

Manipulates an independent variable to determine whether it causes changes in the dependent variable.

Population

The entire group the researcher wants to draw conclusions about.

Sample

A smaller group selected from the population to participate in the study.

Within-Subjects Design (Repeated Measures)

The same participants complete every condition of the experiment.

Between-Groups Design (Independent Groups/Independent Samples)

Different participants complete different conditions.

Matched-Pairs Design

Participants are matched on an important characteristic before being randomly assigned to different conditions.

Single-Blind Design

Participants do not know which condition they are in.

Double-Blind Design

Neither participants nor researchers know who is in which condition.

Standardisation

Keeping all testing conditions the same to minimise confounding variables.

Randomisation

Randomly assigning participants to conditions to reduce participant differences.