During a Longitudinal Self-Esteem Study Conducted at a High School,the

Multiple Choice

During a longitudinal self-esteem study conducted at a high school,the experimental group learns that they have to spend an extra half-hour each day reviewing self-esteem building activities while their counterparts in the control group have an extended lunch.Angry about the difference,many students opt to leave the experimental group.This is an example of what form of invalidity?

A) maturation
B) compensatory rivalry
C) instrumentation
D) causal time order
E) testing