Headache relief Doctors identify “chronic tensiontype headaches” as headaches that occur almost daily for at least six months. Can antidepressant medications or stress management training reduce the number and severity of these headaches? Are both together more effective than either alone? Researchers want to compare four treatments: antidepressant alone, placebo alone, antidepressant plus stress management, and placebo plus stress management.

Describe a completely randomized design involving 36 headache sufferers who are willing to participate in this experiment. Write a few sentences describing how you would implement your design.