21. Nace et al. (A-34) conducted a study to assess the complex relationship between substance abuse and personality disorders. The authors determined the prevalence of personality disorders in a group of middle-class substance abusers and compared the subjects who had personality disorders with those who did not. Among the data reported were the following statistics on the depression component of the Minnesota Multiphasic Personality Inventory (MMPI).

With Without Personality Disorders Personality Disorders 57 70.63 16.27 43 64.33 12.99 SOURCE: Edgar P. Nace, Carlos W. Davis, and Joseph P. Gaspari, "Axis I Comorbidity in Substance Abusers," American Journal of Psychiatg, 148

(1991), 118-120.

May we conclude on the basis of these data that, in general, substance abusers with and without personality disorders differ with respect to their mean scores on the depression component of the MMPI? Let a = .05.