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.
Members of the Lemba ethnic group from southern Africa.
Therapeutic Communication Skills
Dipole interaction of E. coli enzyme structure
Interaction of RF2 with a UGA stop codon in the decoding center
Teaching Models: Designing Instruction for 21st Century Learners
Deoxynucleotides (top) have an OH group at the position in the deoxyribose molecule