"More than half of California's doctors say they are so frustrated with managed care they will quit, retire early, or leave the state within three years." This conclusion from an article titled "Doctors Feeling Pessimistic, Study Finds" (San Luis Obispo Tribune, July 15, 2001) was based on a mail survey conducted by the California Medical Association. Surveys were mailed to 19,000 California doctors, and 2000 completed surveys were returned. Describe any concerns you have regarding the conclusion drawn.