Statistical Software The statistical software packages SAS version 922 SAS Institute Inc Cary NC and Spotfire S-plus version 82 TIBCO Inc Palo A lto CA were used to conduct the statistical analyses. A p005 decision rule was established a priori as the null hypothesis rejection criterion for the statistical test of association. Regression Data Science Learning Ap Psychology Research Skills Moderator variable - In general terms a moderator is a qualitative eg sex race class or quantitative eg level of reward variable that affects the direction andor strength of the relation between an independent or predictor variable and a dependent or criterion variable.