A test designed to predict a particular criterion is most valid when the base rate is 50%

Your text discusses a case in which a researcher tries to test the effectiveness of a form of psychotherapy for depression by administering psychotherapy to depressed adolescents and seeing if they are still depressed 3 months later. Your book notes that many adolescents who are depressed at a given time will be happier later even without psychotherapy. For this reason, the passage of time is discussed as a potential source of:

a. internal invalidity b. external invalidity c. confusion over direction of causation d. a sleeper effect

During the early stages of self-improvement, people tend to express a lot of

a. self-acceptance b. rejection of the therapist c. self-disparagement d. self-insight