Untitled Flashcards Set

Independent Variable

The causal variable that is manipulated in an experiment, typically plotted on the x-axis.

Dependent Variable

The outcome variable in an experiment that is measured and is affected by changes in the independent variable, typically plotted on the y-axis.

Control Variables

Variables that are held constant to eliminate alternative explanations and increase internal validity.

Covariance

The relationship between the independent variable and the dependent variable, indicating that different levels of the independent variable are associated with different levels of the dependent variable.

Temporal Precedence

The principle that the causal variable must occur before the outcome variable in order to demonstrate causality.

Internal Validity

The degree to which a study design rules out alternative explanations for results.

Design Confound

An error in the design of an experiment wherein a second variable varies systematically along with the independent variable, threatening internal validity.

Systematic Variability

When the levels of a variable coincide in a predictable way with group membership, creating a potential confound.

Unsystematic Variability

When the levels of a variable fluctuate independently of group membership, contributing to variability within the groups.

Selection Effects

When participants' characteristics differ systematically between groups, potentially affecting the results of an experiment.

Independent Groups Design

A design where separate groups of participants are assigned to different levels of the independent variable.

Within-Groups Design

A design where each participant is exposed to all levels of the independent variable.

Posttest Only Design

Participants are randomly assigned to groups and tested on the dependent variable once after exposure to the independent variable.

Pretest/Posttest Design

Participants are randomly assigned to groups and are tested on the dependent variable both before and after exposure to the independent variable.

Counterbalancing

A method used to control for order effects by presenting the levels of the independent variable in different sequences to participants.

Confidence Intervals

A range of values that likely contain the true parameter, indicating the reliability of an estimate.

Maturation

Natural changes in behavior that occur over time, which can threaten the validity of an experiment.

Regression to the Mean

The phenomenon where extreme scores tend to move closer to the average upon retesting.

Attrition

When participants drop out of a study, potentially biasing the results.

Instrumentation Error

Changes in measurement instruments over time that can affect the results.

Demand Characteristics

When participants alter their behavior due to guessing the purpose of a study.

Main Effects

The overall impact of one independent variable on the dependent variable, averaging across levels of other independent variables.

Interaction Effect

When the effect of one independent variable depends on the level of another independent variable.

Mixed Designs

Research designs that include both independent and dependent variables, where at least one independent variable is manipulated between groups.

Nonequivalent Control Group Design

A study where participants are not randomly assigned to groups and are tested either once or before and after an intervention.