Lecture Notes: Research Methods in Psychology (Descriptive, Correlational, and Experimental)

A set of vocabulary-style flashcards covering key concepts from the lecture notes on research methods in psychology, including descriptive, correlational, and experimental designs, ethics, sampling, and statistics.

Bystander effect

The phenomenon whereby the presence of others reduces the likelihood that an individual will intervene to help in an emergency.

Descriptive research

Research whose purpose is to observe and record behavior without manipulating variables; includes naturalistic observation and case studies.

Naturalistic observation

Observing behaviors in participants' natural environment without interaction or intervention.

Case study

An in-depth study of a single person or a small group, often to explore rare or unique conditions.

Self-report bias

Errors that occur when participants describe their thoughts, feelings, or behaviors rather than being measured directly.

Social desirability bias

Tendency for people to answer in ways that will look good to others, affecting honesty in self-reports.

Wording effects

The way a question is phrased can influence the answers given.

Correlational research

Research aimed at identifying relationships between variables, using the correlation coefficient (r) to indicate strength and direction.

Correlation coefficient (r)

A statistic that measures the strength and direction of a linear relationship between two variables, ranging from -1.00 to 1.00.

Positive correlation

A relationship in which both variables move in the same direction (both increase or both decrease).

Negative correlation

A relationship in which the variables move in opposite directions (one increases, the other decreases).

Strength of correlation categories

Guidelines for interpreting r: near ±1.00 is very strong, ±0.76 to ±0.99 very strong, ±0.51 to ±0.75 strong, ±0.26 to ±0.50 moderate, ±0.01 to ±0.25 weak, and 0.00 none.

Correlation vs causation

Correlation does not equal causation; correlations do not prove that one variable causes the other due to potential confounds and directionality issues.

Descriptive statistics

Statistics that describe and summarize data from a sample (e.g., mean, median, mode, range, standard deviation).

Mean

The average of a set of scores.

Median

The middle value in a distribution; used when data are skewed or contain outliers.

Mode

The most frequently occurring value in a distribution.

Standard deviation

A measure of how spread out scores are around the mean; larger SD means more variability.

Range

The difference between the highest and lowest scores in a distribution; sensitive to outliers.

Percentile rank

The percentage of scores in a distribution that fall below a given score.

Normal distribution

A bell-shaped distribution where most scores cluster around the mean.

Skewness

Asymmetry in a distribution: positive (right) skew has a longer right tail; negative (left) skew has a longer left tail.

Outlier

An observation that lies far from the rest of the data and can affect summary statistics.

Inferential statistics

Statistics that allow generalization from a sample to the population, including hypothesis testing and significance testing.

Statistical significance

A result is statistically significant when it is unlikely to have occurred by chance alone (commonly p < .05).

Effect size

A measure of the magnitude or practical significance of a finding, indicating how large the observed effect is.

Meta-analysis

A method that combines results from multiple studies to derive a more precise overall effect.

Hypothesis

A testable statement about the relationship between variables; it should be falsifiable.

Operational definitions

Clear definitions of how to measure or identify variables so that studies can be replicated.

Independent variable

The condition that the experimenter deliberately manipulates.

Dependent variable

The outcome or measure that is observed and recorded.

Random assignment

Assigning participants to experimental or control groups by chance, ensuring equal probability of group assignment.

Experimental group

The group that receives the treatment or manipulation of the independent variable.

Control group

The group that does not receive the primary treatment and serves as a baseline for comparison.

Confounding variable

An extraneous variable that can affect the dependent variable and lead to erroneous conclusions if not controlled.

Confederate

A person who pretends to be a participant but is actually working with the researcher in an experiment.

Double-blind study

Neither participants nor researchers know which condition participants are in, reducing both participant and experimenter bias.

Placebo effect

A change in a participant's condition due to the belief that they are receiving an active treatment.

Informed consent

Ethical requirement that participants voluntarily agree to participate and can withdraw at any time.

IACUC

Institutional Animal Care and Use Committee; oversees and regulates the ethical use of animals in research.