Preliminary bivariate tests were also conducted to gain an initial understanding of the relationship between the exogenous variables and the outcome variables of interest. These tests revealed several significant associations. In particular, being male, being White, and being a science major were all positively associated with scores on the ACS exam (results not shown), and these variables were therefore included in the later regression models to control for their effects on the outcome variables. Age was negatively associated with exam scores and was included in the models as well. Finally, students' composite ACT scores and cumulative GPAs were included in the models due to their likely association with exam performance (ACT, 1998, 2007).