Statistics and Research

Regression

Models how one continuous variable predicts another; distinguishes independent and dependent variables.

Linear Regression

Models the linear relationship between two continuous variables using a line of best fit.

Correlation

Measures the strength and direction of the relationship between two continuous variables without assigning causation.

Regression vs Correlation

Regression predicts one variable from another; correlation measures relationship strength and direction without assigning independent or dependent variables.

Chi-square test

Tests whether categorical variables are associated or whether observed categorical counts differ from expected counts.

Cross-sectional study

Look at a group of different people at one moment in time

Cohort study

Following a subset of population over a lifetime

Longtiduianl study

Data is gathered for the same subjects repeatedly over a period of time

Case-control study

An observational study that compares people with a condition (cases) to people without it (controls) to determine differences in their past exposures or risk factors.

Quasi-Experimental Design

A study that examines the effect of an independent variable on a dependent variable without randomly assigning participants to groups.

Validity

Accuracy in measuring something

Internal validity

The extent to which a study establishes that the independent variable caused the observed effect on the dependent variable, rather than confounding variables.

External validity

Whether results of the study can be generalized to other people and situations

Test validity

The extent to which a test accurately measures what it is intended to measure.

Criterion validity

The extent to which a test’s results correlate with an established measure or accurately predict a relevant outcome.