1. Explain how the process of counterbalancing attempts to keep order effects from becoming a confounding variable in a within-subjects design.
2. Explain how statistical regression and instrumentation threaten the internal validity of within-subjects designs.
3. Describe the disadvantages of a multiple-treatment design, compared to a two-treatment design, for a within-subjects experiment.
4. Explain how a matched-subjects design attempts to achieve all the advantages of both between-subjects and within-subjects designs.