Laura Conducts a Study to Determine Whether Her New "Puppet

Multiple Choice

Laura conducts a study to determine whether her new "puppet" therapy works better than the traditional "talking" therapy.After randomly assigning her own patients to either the "puppet" or "talking" group,Laura herself administers the therapy.This study's most obvious flaw is ____.

A) random variables
B) experimenter bias
C) the placebo effect
D) participant expectations