Exercise 5.7 In an effort to determine the effectiveness of light therapy to alleviate depression, you recruit a group of subjects who have been diagnosed as depressed. The subjects are randomly assigned to one of two groups: The control group will receive no light therapy, and the treatment group will get light therapy for 1 hour on even-numbered days over the course of 1 month, at which time 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 05 - Exercise 07A.sav Codebook Variable: group Definition: Light therapy group assignment Type: Categorical (1 = No light therapy, 2 = Light therapy: even days)

Variable: mood Definition: Acme M