Data analysis plays a prominent role in various facets of modern life: Schools evaluate and revise programs on the basis of test scores; policymakers make decisions on the basis of information gleaned from polling data; supermarkets stock shelves on the basis of data collected at checkout lanes. Data analysis provides teachers with new tools and new methods for exploring mathematical concepts. In this article, the authors illustrate ways in which data simulation and visualization tools have opened up new pathways for learning as they explore several rich mathematics tasks by using Fathom dynamic data analysis software. As their examples suggest, the availability of intuitive, drag-and-drop data visualization and simulation tools blurs the distinctions between algebra, geometry, and data analysis in the secondary school curriculum. (Contains 16 figures and a bibliography.)