A therapist believes that teaching anxious clients group interaction skills can lessen their anxiety. She gives an anxiety test, chooses the most anxious 10 percent of people, and then teaches them group interaction skills. On giving them a second anxiety test she discovers that their anxiety is significantly lower. If she concludes that the teaching has caused lessened anxiety she is ignoring ____ as a potential threat to internal validity.
A) selection
B) statistical regression
C) mortality
D) history
Question 2
I give a questionnaire to a group of people measuring their favorability toward nuclear power plants and then I send these people educational pamphlets informing them about nuclear power. Finally I again give them the original questionnaire to see if their favorability has changed. A possible threat to internal validity in this design is
A) mortality.
B) testing.
C) selection.
D) history.
Photograph of an occupational therapist assisting a patient with learning independence in activities
(A) Each bronchiole terminates in an alveolar sac, a group of alveoli; (B) alveoli encased by networ
The Local Group
Fine motor skills involve coordinating the many small muscles of the wrists, hands, and fingers.
Surface molecules involved in the interaction between an antigen-presenting cell and a CD4+ T cell.
Group of Geese