This book examines five big ideas and twenty-four related essential understandings for teaching statistics in grades 9-12. The authors distinguish mathematical and statistical models, explore distributions as descriptions of variability in data, focus on the fundamentals of testing hypotheses to draw conclusions from data, highlight the importance of the data collection method, and recognize the need to examine bias, precision, and sampling method in evaluating statistical estimators. Recognizing that analyzing data is an important part of understanding the world, the authors discuss the growth of students ideas about statistics and examine challenges to teaching, learning, and assessment. They intersperse their discussion with questions for teachers reflection. Brief Contents: Statistics: The big ideas and essential understandings -- Connections: Loosing back and ahead in learning -- Challenges: Learning, teaching, and assessing -- Appendix 1: Glossary of Statistical terms -- Appendix 2:.