People high or low in self-esteem react differently

A researcher wishes to examine whether people high or low in self-esteem react differently to different kinds of therapy for depression. She takes a sample of 120 people (half have high self-esteem and half have low self-esteem) and randomly assigns them to one of three conditions (humanistic therapy, cognitive-behavioral therapy, and a control group of no therapy). She records their level of depression after 3 months of therapy. Scores can range from 1 (very little depression) to 30 (extreme depression).”