What is the difference between a random sample and random assignment?

A random sample means every member of the population has an equal chance of being selected for the study. It allows researchers to generalize findings to the broader population. Random assignment means participants already in the study are randomly placed into experimental or control groups. It ensures that pre-existing differences between participants are evenly distributed across groups, reducing confounding variables. A study can have random assignment without random sampling, and vice versa. The AP exam tests both concepts frequently.