Chapter 7 Using Multivariate Statistics Multiple Regression Multiple Correlation What’s the difference between regression and correlation? Validity Generalization Chap 7 Multivariate Statistics

COMPENSATORY PREDICTION MODELS Regression Equations Y = a + b1X1 + b2X2 what’s the difference between b and β weights? Why use one or the other? Multiple Correlation How are the correlations among the predictors related to the multiple R? Would you want high correlations among predictors? Suppressors and Moderator Variables Suppressor variables explained Suppressors How could reading ability act as a suppressor for security guard performance? Moderators How could social skills moderate the conscientiousness-performance relationship? Other Additive Composites Unit weighting is usually sufficient Could you add veterans’ preference or religious preference? Chap 7 Multivariate Statistics

NONCOMPENSATORY PREDITION MODELS Multiple Cutoff Models Two situations warrant it: 1. vital trait 2. if variance is too low (small) to yield sig r. What can happen if cutoffs are all very low? What can happen if cutoffs are all very high? Sequential Hurdles When could this be useful? Chap 7 Multivariate Statistics

REPLICATION AND CROSS-VALIDATION What IS cross validation? Why is it necessary? Chap 7 Multivariate Statistics

VG Situational Specificity v. Validity Generalization Special form of meta-analysis All validity coefficients (across studies) Would be the same if not for Artifacts Hunter & Schmidt (‘90) If var in coefficients is explained by artifacts, reject SS Reject Sit Spec if artifacts 75 % of the variance in coefficients is explained by known artifacts Chap 7 Multivariate Statistics

VG Three possible outcomes Refute or support Situational Specificity Refute or support VG Chap 7 Multivariate Statistics