Managing Data THE MATERIAL covered in this chapter, when mastered, will provide a firm grounding in data management that will serve you well throughout the remaining chapters of this book. Rarely will you complete an analysis session without making use of some of the features in this chapter. Occasionally you may have a single data file and want to run a single operation. If so, reference to this chapter may be unnecessary; just use the data as you originally entered and formatted them. Chapter 3 explains how to create and format a data file, and Chapters 6-27 provide lucid step-by-step instructions about how to analyze data. However, it is common to want to analyze variables that are not in the original data file but are derived from the original variables (such as total points, percentage of possible points, or others). It is also sometimes desirable to display the data differently (e.g., alphabetically by student last names, by total points from high to low, or class records listed by sections); to code variables differently (e.g., 90-100 coded A, 80-89 coded B, and so forth); to perform analyses on only a certain portion of the data set (e.g., scores for females, GPAs for Whites, final percentages for Sophomores, final grades for Section 2, etc.); or if the sections were in three different files, to merge the files to gain a clearer picture of characteristics of the entire class.