A Teacher Believes That One Group of Children Is Very

Multiple Choice

A teacher believes that one group of children is very bright and that a second group is below average in ability.Actually, the groups are identical, but the first group progresses more rapidly than the second.This demonstrates

A) the self-fulfilling prophecy.
B) the placebo effect in a natural experiment.
C) observer bias in naturalistic observation.
D) the ethical problems of field experiments.