Dr. Franklin investigated the relationship between stress and physical illness. She persuaded a high school principal to require all female athletes in the school to participate in her study. She explained the purpose of her research to the athletes and asked them to use a standard form to rate the severity
of their stress over the last six months. More than 250 athletes completed the form. Then Dr. Franklin analyzed the forms returned by the first 100
athletes. She requested the attendance records from the nurse's office for each of those athletes to verify the number of days absent due to illness
during the same six-month period. In the debriefing summary that Dr. Franklin sent to the 100 athletes after she completed the study, she stated that
athletes who reported more stress also experienced more frequent illness. Dr. Franklin concluded that stress causes physical illness.
-- Describe the operational definitions of the TWO key variables that Dr. Franklin used in the study.
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