Exercise 6.7 In an effort to determine the effectiveness of light therapy to alleviate depression, you recruit a group of subjects who have been diagnosed with depression. The subjects are randomly assigned to one of three groups: Group 1 will be the control group—members of this group will receive no light therapy. Members of Group 2 will get light therapy for 1 hour on even-numbered days over the course of 1 month.

Members of Group 3 will get light therapy every day for 1 hour over the course of 1 month. After 1 month, all participants will complete the Acme Mood Scale, consisting of 10 questions; this instrument renders a score between 1 and 100 (1 = extremely bad mood, 100 =

extremely good mood).

Data set: Ch 06 - Exercise 07A.sav Codebook Variable: group Definition: Light therapy group assignment Type: Categorical (1 = No light therapy, 2 = Light therapy: even days, 3 = Light therapy: every day)

Variable: mood Definition: Acme Mood Scale score Type: Continuous (1 = extremely bad mood, 100 = extremely good mood)

1. Write the hypotheses.