UNIT 0

Vocabulary and key concepts from the AP Psychology Unit 1 review lecture covering research methods, statistics, ethics, and cognitive biases.

Experimental Research

Research that shows cause and effect by changing one variable to see its impact.

Independent Variable

The variable that is changed by the researcher.

Dependent Variable

The variable measured to see if it changes due to the independent variable.

Confounding Variables

Other factors that may affect the dependent variable.

Random Assignment

Randomly placing participants into groups to avoid bias.

Experimental Group

The group that receives the treatment in a study.

Control Group

The group that does not receive treatment, used for comparison.

Placebo

A fake treatment that looks real, used to test if effects are due to belief.

Double-blind Procedures

Both participants and researchers don't know who is in which group to reduce bias.

Operational Definition

How a variable will be measured in a study.

Replication

Repeating a study to see if similar results occur.

Likert Scales

Rating scales that measure how much someone agrees or disagrees.

Hypothesis

A testable prediction about the relationship between variables.

Non-experimental Research

Research methods that cannot establish cause and effect.

Case Studies

In-depth studies of a single person or group.

Correlational Research

Examines the relationship between two variables without altering them.

Third Variable Problem

An unseen variable that may influence the results.

Correlational Coefficient

A number between $-1$ and $+1$ showing how strongly two variables are related.

Positive Correlation

Both variables increase or decrease together.

Negative Correlation

One variable increases while the other decreases.

Meta-analysis

Combining results from multiple studies to find broader trends.

Naturalistic Observation

Watching behavior in a natural setting without interference.

Random Sampling

Choosing participants so everyone has an equal chance of being selected.

Convenience Sampling

Choosing participants based on easy access.

Sampling Bias

When certain members of a population are overrepresented.

Institutional Review Board (IRB)

A board that ensures ethical standards in research are met.

Informed Consent

Participants must be told about the study and agree to join.

Confederates

Actors in a study pretending to be participants.

Debriefing

Explaining the study's true purpose to participants after it ends.

Mean

The average of a set of numbers.

Median

The middle number in a sorted list.

Mode

The most common value in a dataset.

Range

Difference between the highest and lowest values.

Standard Deviation

How spread out values are from the average.

Normal Curve

A bell-shaped distribution where most values are near the average.

Positively Skewed Distribution

A distribution with a long tail to the right.

Negatively Skewed Distribution

A distribution with a long tail to the left.

Bimodal Distribution

A distribution with two peaks.

Percentile Rank

The percentage of scores below a certain score.

Regression Towards the Mean

Extreme scores tend to be followed by average ones.

Effect Size

Indicates how strong a relationship is, categorized as small, medium, or large.

Statistical Significance

Results are unlikely due to chance.

Hindsight Bias

Seeing events as more predictable after they happen.

Confirmation Bias

Favoring information that confirms existing beliefs.

Overconfidence

Being more confident in judgment than justified.

Social Desirability Bias

Answering in a way that aligns with social norms.

Experimenter Bias

Researcher expectations unintentionally affecting results.