stats - Data Collection Methods - 3

observational study

A study where researchers observe without controlling variables; cannot prove causation.

experiment

A study where researchers control explanatory variables, often through random assignment.

random assignment

assigning subjects to treatment/control groups by chance to avoid confounding

treatment group

The group that receives the experimental treatment.

control group

The group that does not receive the treatment.

randomized comparative experiment

Subjects are randomly assigned to treatment or control and results are compared.

matched pairs design

Each subject receives both treatments (or is paired with a similar subject) to compare results.