The tendency for some kinds of people to be more likely than others to drop out of a study is known as

A) systematic variation.
B) equilibration.
C) evolution.
D) selective attrition.

Selective Attrition

The process by which participants drop out of a long-term experiment or study at a rate that is not random, potentially biasing the results.

Drop Out

The act of leaving a school, course, or activity before completion, often associated with educational contexts.

Study

The act of dedicating time and attention to acquiring knowledge on a specific subject through reading, research, or practice.