This third edition of the popular text capitalizes on a successful approach of using definitional formulas to emphasize concepts of statistics, rather than rote memorization. This approach constantly reminds students of the logic behind what they are learning, and each procedure is taught both verbally and numerically, which permanently establishes the concepts in the students' minds. Thoroughly revised with new content, many new examples, new pedagogical features, and doubling the number of practice problems, this text takes the reader from basic procedures through analysis of variance (ANOVA), and not only teaches statistics, but prepares students to read and understand research articles.