Research
Following the same group of students for 10 years.
Longitudinal study
The variable the researcher manipulates or control.
Independent variable
A +0.80 correlation means this.
A: Strong positive relationship
Observing behavior in a natural environment.
Naturalistic observation
The extent to which a test measures what it claims to measure.
Validity
Comparing 8, 12, and 16‑year‑olds at one time.
Cross‑sectional study
The variable being measured.
Dependent variable
A –0.20 correlation means this.
Weak negative relationship
Gathering self‑reported attitudes or behaviors.
Survey
Manipulating noise level to test performance.
Experiment
Studying one rare individual in depth.
Case study
Assigning participants to groups by chance.
Random assignment
Correlation does NOT prove this.
A: Causation
When participants give socially acceptable answers.
Social desirability bias
Participants change behavior because they know they’re being observed.
Hawthorne effect
Measuring two variables without manipulation.
Correlational study
A fake treatment used to control expectations.
Placebo
A third variable that explains a correlation.
Confounding variable
A small group representing a larger population.
Sample
Watching shoppers without interacting.
Naturalistic observation
Manipulating one variable to observe its effect.
Experiment
Neither participants nor researchers know group assignments.
Double‑blind procedure
A graph used to show correlational data.
Scatterplot
Every member of the population has an equal chance of being selected.
Random sample
A variable that systematically varies with the IV.
Confounding variable