A therapist would like to measure the effectiveness of a procedure for treating depression. A sample of n=16 depressed clients is obtained and each person's level of depression is measured using a standardized questionnaire before they begin the therapy program. 2 weeks after therapy, each client's level of depression is measured again. For this sample, the average level of depression dropped by Dm=6.8 points following therapy. The difference scores had a s2 of 64
It is hypothesized that scores on a standardized depression questionnaire will significantly decrease after therapeutic intervention in a sample of depressed clients. Test at the .05 level of significance