I. For each of the following experiments, assume large, randomly selected and assigned groups and a statistically significant difference between the results of the two groups in the study. Experiment A. The effect of anti-anxiety medications on recovery from knee surgery. 1. What is the independent variable? a. recovery from surgery b. time needed to run a mile c. the anti-anxiety medications d. knowledge of whether they are receiving pain medication or placebo e. the correlation between the independent and dependent variables