A psychologist would like to measure the effectiveness of a new treatment for Generalized Anxiety Disorder.

1. A psychologist would like to measure the effectiveness of a new treatment for Generalized Anxiety Disorder. To do so, she first measures the level of anxiety experienced by her patients before they receive any treatment. She uses a self-report measure called the State-Trait Anxiety Inventory (STAI). Higher scores indicate more anxiety. She then provides the new treatment, which takes 12 sessions. After the 12 sessions are completed, she again has her patients complete the STAI to measure their anxiety symptoms. The data are as follows:

Patient

Pre-treatment STAI score

Post-treatment STAI score

A

45

28

B

38

33

C

27

28

D

42

31

E

29

28

F

35

22

G

31

19

H

32

31

1. What kind of a research design is the psychologist using? (circle one)

Independent measures (between subjects)

Repeated measures (within subjects)

1. What is the dependent variable in this study? (be specific)
2. Using the appropriate statistical procedure, conduct a hypothesis test to determine whether the treatment was effective. Use a two-tailed test, α = .05. BE SURE TO INCLUDE ALL 4 STEPS OF THE HYPOTHESIS-TESTING PROCEDURE! Don't forget to calculate the effect size if necessary.