Topic: Observational Studies and Experiments

Treatments, Control Groups, and Comparison Groups

Replication and Experimental Units

Reading a Study’s Design from Its Methods

Random Assignment Versus Random Sampling

Randomized Block Designs

Random Assignment and Its Purpose

Prospective and Retrospective Observational Studies

Planning a Completely Randomized Experiment

Observational Studies and Randomized Experiments

Natural Experiments and Quasi-Experiments