Use the “Kranzler et al simulated .sav” (or “Kranzler et al simulated.xls”) data set found on the Web site (www.tzkeith.com). Center the CBM scores and create a Sex by CBM cross product using the centered variable. Conduct an analysis for predictive bias using the centered data. Do the results match those presented here? Try conducting the analysis using the uncentered data (and cross product based on uncentered data), as was done in Kranzler et al. (1999). Compare the correlations, coefficients, and graphs from the two analyses. Would your interpretation be the same? Compare the two printouts;

see if you can develop a sense of why the differences occur. It is also worth focusing on the correlation matrices and then the standard errors of the regression coefficients.

Reread the section discussing the advantages of centering.