A psychologist who has been working with a group of patients diagnosed with

depression for many years has noticed that they are not really responding to her regular treatment methods. The psychologist decides to expose all of her patients to a new treatment method for 3 months and then test them again. The table below shows their depression scores before and after the new treatment.

Before treatment

15

17

13

10

19

11

12

After treatment

17

20

13

13

21

14

15

a. Use the data in the table above to test the hypothesis. Show all hypothesis tests steps and manual calculations. Use alpha level .01.

[15 Marks]