This book assists high school teachers in honing their students' thinking by introducing them to two approaches to probability and exploring both approaches in real-world contexts. The first approach, which interprets probability as relative frequency over the long run, uses actual or simulated data from many experiments to arrive at empirical probabilities. The second approach analyses outcomes abstractly to arrive at theoretical probabilities. The supplemental CD-ROM features interactive electronic activities, master copies of activity pages for students and additional readings for teachers.