A researcher wants to investigate the influence of a new medication on anxiety. the researcher assigns participants to one of three groups: a placebo group, a 75mg group, or a 150 mg group. Two months after the onset of treatment, patients fill out a widely-used anxiety inventory to see if there are differences in anxiety.

1 - What is the independent variable?

2 - What is the dependent variable?

3 - What might be a confounding variable?