Dr. Sheffield is a clinical psychologist who specializes in treating pathological gambling. Pathological gambling is defined as being unable to resist impulses to gamble. Bothered by not having a good measure that he can give to clients to determine whether they are suffering from this condition, he creates a new measure of pathological gambling. The measure has 15 questions, and it takes 20 minutes to complete. Refer to Research Study 3.2 to answer the following five questions. To test his measure, Dr. Sheffield gives his measure to a group of people in Gamblers Anonymous (GA) and another group in Alcoholics Anonymous (AA). He finds that people in the GA group have higher scores on his new measure than people in the AA group. Why did Dr. Sheffield do this