PSYCHOLOGY 502 Research Methods, Short-answer Essays( about 2 pages)

Can you help me understand this Psychology question?

Short–answer Essays –To receive full credit, ALL parts of a question must be addressed.

1.)Describe the differences between single-factor designs and factorial designs. Explain the unique advantages of factorial designs over single-factor designs.

2.)Provide an example of a study in which both main effects and interactions are significant. Explain how the main effects and interactions in this study are to be interpreted.

3.)Explain under what circumstances quasi-experimental designs are used and the reasons for their use.

4.)Why is internal validity a major concern in experimental studies whereas for quasi–experimental studies the major concern is external validity? In your response, be certain to indicate circumstances in which internal and external validity may be reduced in both of these types of studies.