AP Psych Unit 0: Science Practices

Hindsight Bias

Believing you 'knew it all along.'

Confirmation Bias

Seeking information that supports pre-existing beliefs.

Overconfidence

Thinking you're more accurate than reality.

Peer Reviewers

Experts who evaluate scientific work.

Theory

Explanation based on evidence.

Hypothesis

A testable prediction based on a theory.

Falsifiable

Can be proven false by evidence.

Operational Definition

Describes variables in measurable terms.

Replication

Repeating a study to obtain consistent results.

Case Study

An in-depth study of one subject.

Meta-Analysis

Combines results of many studies.

Naturalistic Observation

Watching behavior in a natural setting.

Survey

A questionnaire to gather self-reported data.

Social Desirability Bias

Providing socially approved answers.

Self-Report Bias

Inaccurate personal reporting.

Experimenter Bias

When a researcher unintentionally influences the outcome.

Population

The entire group being studied.

Sample

A subset of the population being studied.

Sampling Bias

When a sample doesn’t accurately represent the population.

Random Sample

Everyone in the population has an equal chance of selection.

Convenience Sampling

Sampling from the easiest to reach subjects.

Representative Sample

A sample that accurately reflects population characteristics.

Experimental Methodology

Manipulates variables to determine cause.

Non-Experimental Methodology

Observes without altering variables.

Correlation

A relationship between two variables.

Correlation Coefficient

Indicates strength and direction of a correlation.

Variable

Anything measurable or changeable.

Scatterplot

A graph showing relationships between variables.

Illusory Correlation

Perceiving a relationship where none exists.

Directionality Problem

Uncertainty about which variable influences the other.

Third Variable Problem

An unmeasured variable that accounts for two measured variables.

Regression Toward the Mean

Extreme scores move toward the average.

Experiment

A controlled test of variables.

Experimental Group

The group receiving treatment or condition.

Control Group

The group that receives no treatment; for comparison.

Independent Variable

The variable manipulated by the researcher.

Dependent Variable

The measured outcome of an experiment.

Random Assignment

Subjects are randomly assigned to different groups.

Single-Blind Procedure

Participants are unaware of which group they are in.

Double-Blind Procedure

Both participants and researchers are unaware of the groups.

Placebo

An inactive substance used in a control group.

Placebo Effect

The response to a fake treatment.

Confounding Variable

A variable affecting the dependent variable besides the independent variable.

Validity

The extent to which a measure reflects what it claims to measure.

Quantitative Research

Research that uses numbers and statistics.

Qualitative Research

Research that uses open-ended, descriptive data.

Likert Scales

Rating scales used to assess opinions.

Institutional Review

Committee that approves ethical research.

Informed Consent

Participant agrees after being informed of risks.

Informed Assent

Minor’s agreement to participate in research.

Protect from Harm

Ensures no unnecessary physical or psychological harm is done.

Confidentiality

Keeping personal data private.

Research Confederates

Actors used within the context of an experiment.

Debriefing

Explaining the study to participants afterward.

Histogram

A bar graph of data distribution.

Measure of Central Tendency

Shows the center of a dataset; includes mode, mean, and median.

Mode

The most frequent score in a dataset.

Mean

The average score calculated by summing all scores divided by the number of scores.

Median

The middle score in a dataset when ordered.

Percentile Rank

Indicates a score's position relative to others in the distribution.

Skewed Distribution

When scores are not symmetrically distributed, leaning left or right.

Bimodal Distribution

A distribution with two high frequency scores (peaks).

Range

The difference between the highest and lowest scores.

Standard Deviation

Describes how spread out scores are around the mean.

Normal Curve

A bell-shaped symmetrical distribution of data.

Inferential Statistics

Statistical methods to draw conclusions about a population based on sample data.

Statistical Significance

Indicates that a result is unlikely to be due to chance.

Effect Size

Indicates the strength of an experimental outcome.