Dr Hyper Treated 20 Patients Using a New Therapeutic Procedure

Multiple Choice

Dr. Hyper treated 20 patients using a new therapeutic procedure. An outside observer rated the children's activity level on a laboratory task before and after the treatment; 80% of the children decreased their activity level following treatment, and Dr. Hyper concluded that the procedure was highly effective. Which of the following is a likely a confound in Dr. Hyper's experiment?

A) The children were not truly hyperactive.
B) The children decreased their activity level because the task was no longer novel.
C) The person who rated the children's activity level was biased.
D) The children improved because they were just trying to please the experimenter.