Teaching introductory statistics using curricula focused on modeling and simulation is becoming increasingly common in introductory statistics courses and touted as a more beneficial approach for fostering students' statistical thinking. Yet, surprisingly little research has been conducted to study the impact of modeling and simulation curricula on student thinking, nor is there much research on how students make sense of the computer models they construct. The work presented here utilizes a framework developed by Biehler, Frischemeier, and Podworny (2015) for comparing two groups problems via a modeling and simulation approach using TinkerPlots™. Our work makes a contribution to the field by delving deeper into student reasoning as students create TinkerPlots™ models to solve a comparing two groups problem.