This needs to be answered
Question #4
Dr. Dove was interested in the effects of eating chocolate on well-being. She randomly assigned 20 participants to two groups. Both groups ate as they normally would, but one group was instructed to eat a 1-ounce square of dark chocolate after lunch. After 4 weeks on this diet, they completed a questionnaire measuring their level of well-being (happiness, contentment). Dr. Dove was surprised to find the chocolate had no effect: Both groups, on average, scored the same on the well-being measure. Help Dr. Dove troubleshoot her study. What should she do next time to improve her chances of finding a significant effect for the chocolate-enhanced diet, if eating chocolate really does improve well-being?