A social psychologist at Children's Protective Services (CPS) works with youth 18 years of age and older who previously have been in custody at CPS, but now have been released. She decides to conduct a study on the extent to which these youths can live independently upon their release, measured by the outcome variable a 20-point Independent Living Scale (ILS) with a higher score indicating higher ability to live independently. She recruited 73 youths who had previously been in custody and administered questionnaires that measured three continuous predictors: Social Skills Inventory (higher score = better social skills), Social-Doubt Scale (higher score = more social-doubt), and Academic Aptitude Scale (higher score = higher academic aptitude). The literature indicates that Social Skills Inventory is an important predictor of ILS. The remaining predictors were measured to see the unique contribution of other factors to their ability to live independently. The SPSS output tables are given below.