Sampling
This occurs when researchers measure every member of a population.
Census
A survey scale that ranges from strongly agree to strongly disagree.
Likert scale
The statistic that tells how strongly two variables move together.
Correlation coefficient (r)
Imagine tracking contestants from Love Island every summer for 5 years to see how messy they stay. What type of design follows the same people over time?
Longitudinal design
In regression, this variable is the main outcome researchers try to predict.
Criterion variable
The most common sampling method used in behavioral research.
Convenience sampling
A survey question that accidentally asks two questions at once.
Double-barreled question
When two variables increase together (like caffeine and late-night studying).
Positive Correlation
If drama levels on Love is Blind in Week 1 predicts drama in Week 2 for the same variable, this type of correlation shows stability over time.
Autocorrelation
Imagine: Stress → Sleep → Mood. The middle variable explains how the first affects the last.
Mediator
A sampling method where researchers randomly select people within demographic categories.
Stratified random sampling
When participants change behavior because they know they are being observed.
Reactivity
A relationship where performance improves with stress until it suddenly crashes.
Curvilinear Relationship
If researchers correlate crying on camera and screen time in the same episode of The Real Housewives of Salt Lake City, what kind of correlation uses variables measured at the same time?
Cross-sectional correlation
In regression output, this Greek letter shows the direction and strength of each predictor after controlling for the others.
Beta (β)
A biased sampling method where participants volunteer themselves.
Self-selection bias
A survey bias where respondents answer “yes” or “strongly agree” to everything.
Acquiescence
The classic correlation issue where another variable secretly explains the relationship.
Third-variable problem
If follower count at Time 1 predicts brand deals at Time 2, that relationship is this type of correlation.
Cross-lag correlation
If the relationship between stress and grades is stronger for freshmen than seniors, that third variable plays this role.
Moderator
A probability sampling method where researchers randomly select entire groups (clusters) and then measure everyone inside them.
Cluster sampling
An observation method where behavior is recorded without participants knowing they are being observed.
Unobtrusive observation
The three rules required before claiming causation.
Covariance, temporal precedence, internal validity
If follower count predicts future brand deals AND brand deals predict future follower count, researchers call this kind of reinforcing relationship what?
Reciprocal (bidirectional) relationship
A statistical technique that predicts an outcome using several predictors at the same time.
Multiple regression