Type of graph for the effects of cognitive behavioral therapy on depression: A social worker tracked the depression levels of clients being treated with cognitive-behavior therapy for depression. For each client, depression was assessed at week 1 to 20 of therapy. She calculated a mean for all of her clients at week 1, week 2, and so on, all the way to week 20.

a. What are the independent and dependent variables in this study?

b. Are the variables nominal, ordinal, or scale?

c. Which graph or graphs would be the most appropriate to depict the data? Explain why?