In the Text Example of an Experiment Examining the Effect

Multiple Choice

In the text example of an experiment examining the effect of anger on concentration, some of the subjects who were angered simply left the experiment. This example illustrated which of the following problems with experimentation?

A) The Hawthorne effect due to subjects knowledge that they're being observed
B) Confounded variables due to unequal groups of subjects.
C) Order effects due to failure to use counterbalancing.
D) Subject expectancy effects due to their attempts to guess the experimental hypothesis.
E) The placebo effect in which subjects respond as if they had received a treatment when they haven't.