discussed in this book. It is clear that with an understanding of the main ideas of statistics, engaged citizens can grasp what the professional number crunchers have produced and evaluate the results. This book grew out of a course designed by Gudmund R. Iversen to meet the challenges created by this greater reliance on statistical It was one of a series of courses designed at Swarthmore information. College to fulfill the mission of a liberal arts college to educate its students for the challenges of the twenty-first century. The idea was that students should not become so involved with the intricacies of a single discipline that they lose sight of the big picture. These courses were intended to educate students to understand how the major ideas of a field relate to the world. In many respects statistics seemed an ideal subject for one such course. While statistics could be a mystifying, self­ aggrandized, and esoteric discipline, it could also be a key to under­ standing many other disciplines. The course, Stat 1: Statistical Think­ ing, was created to produce this understanding. The course proved to be very popular, and each year it grew in size. Over time the lecture notes for the course became more refined and extensive, and eventu­ ally the course material served as the basis for this book. Fonnulas As most statistics instructors are keenly aware, the teaching of statistics has changed dramatically.