“Few Women Educators Are at the Top in Waukesha County, Survey Shows”; “Alarming Stats on Assaults Lead to Assembly Bill 431”; “Big-Time Athletes Lose in Class, Study Finds.” These headlines, all from one edition of a large metropolitan newspaper, are typical of the increasing importance of data analysis in today's society. We are confronted with quantitative information in every phase of our lives. Decisions on health, citizenship, parenthood, employment, and sports are made using charts, graphs, percentages, probabilities, averages, and forecasts. Workers must read charts and graphs to determine whether a product meets the company's standards. Business personnel are given sheets of data on the basis of which they must decide which company to close, which product to sell, or which drug has dangerous side effects.