In a study of consumer habits, researchers designed a questionnaire to identify compulsive buyers. For a sample of consumers who identified themselves as compulsive buyers, questionnaire scores have a mean of 0.83 and a standard deviation of 0.24. Assume that the subjects were randomly selected and that the sample size was 32. At the 0.01 level of significance, test the claim that the self-identified compulsive-buyer population has a mean greater than 0.21, the mean for the general population. Does the questionnaire seem to be effective in identifying compulsive buyers?