The Myers-Briggs Type Indicator (MBTI) Extraversion-Introversion scale was compared with the Minnesota Multiphasic Personality Inventory (MMPI) 0 scale (Social Introversion) for 18 male and 66 female adult students in introductory courses in psychology, aged 17 to 83 years. A status survey design was used with a priori and post hoc groupings. Independent variables investigated were age, gender, and marital status. Dependent variables were the MBTI Extraversion-Introversion scale and the MMPI 0 scale scores. An analysis of variance was used to test the null hypotheses. Results suggest the following: (1) age and marital status should be investigated simultaneously when using the MMPI 0 scale scores; (2) an association is found between MBTI extraversion-introversion scores and the MMPI 0 score; (3) no association is found for age and the MBTI scores studied; (4) no association is found for gender and the MBTI scale scores studied; (5) no association is found between gender and MMPI 0 scale; (6) no association is found between marital status and MBTI scores studied; and (7) the two scales of the instruments studied appear to give approximately the same information. An appendix contains the authorization to use the case materials in research, teaching, or publishing. Three tables and one figure present study findings. (Contains 43 references.) (SLD)