A simple guide to IBM SPSS® statistics for versions 18.0 & 19.0

Abstract

A tremendous variety of computer software options is available for use in introductory statistics and research methods courses. Although programs designed specifi cally for teaching purposes and/or ease of use have obvious advantages, there are also good reasons to prefer a more advanced, researchoriented program such as SPSS. First, SPSS is in widespread use, so if one moves to another setting to fi nish college, pursue a graduate education, or work in an applied research setting, the odds are good that one version or another of SPSS will be available at the new location. Second, learning a powerful program such as SPSS in an introductory course prepares the student for data analysis in subsequent, more advanced courses, as well as in “real” research projects later on. It might be a little rough at fi rst, but in the long run the extra investment of time and effort early on will pay off. This edition, like the previous versions of this book, was written to cover what the fi rst-time or casual user needs to know—and only what the user needs to know—to conduct data analyses in SPSS at the level of an introductory statistics course in psychology. Other books and manuals have been published with similar intentions, but we have not found one that we felt quite accomplished the goals as simply and inexpensively as we think should be possible. Some, for example, give equal coverage to one or more computer programs in addition to SPSS; the reader interested only in SPSS must sift through (and pay for!) the irrelevant pages to fi nd what he or she needs. Other books attempt to achieve a level of comprehensiveness paralleling that of the program itself, delving into advanced multivariate techniques, complicated data transformation procedures, and so forth that are of little value to the beginning student. Still other books delve deeply into the theory and mathematics of the procedures, and consequently overlap with—and potentially confl ict with—textbook material and classroom instruction. In contrast, our approach is to create a simple anthology of examples to illustrate the kinds of analyses typically covered in an introductory statistics course in psychology, providing just enough explanation of procedures and outputs to permit students to map this material onto their classroom and textbook knowledge. Back in the 1990’s before the Windows operating system was born, the only way to use SPSS was to learn its programming language and type in the appropriate commands. In the Windows versions, SPSS has introduced an interface (which we refer to as the Point-and-Click Method) that eliminates the need to learn any syntax or command language. Rather than typing commands into the program, as was required in SPSS/PC+, the user merely point-and-clicks his or her way through a series of windows and dialog. The user can then examine the output without ever viewing the program code itself—in fact, users must go out of their way to view the internally generated program code at all—and without having to ever learn any syntax or computer programming skills. Although the simplicity of this procedure seems ideal at fi rst, we believe it is at best a two-edged sword. IBM SPSS Statistics also permits the user to type commands the old-fashioned way (which we refer to as the Syntax Method) rather than simply pointing-and-clicking. There are several good reasons for learning how to use SPSS in this way rather than relying exclusively on the Point-and-Click Method. First, we think there is pedagogical value in students’ learning a little computer programming, if only at the simple level of the SPSS command language, as part of an introductory statistics course. Second, for anyone planning to use SPSS for more advanced purposes than completing a few homework assignments, there is simply no escaping SPSS syntax: You’ll probably want to learn it sooner or later. As you move on to more sophisticated uses of the program for real research projects, the advantages of being able to write and edit command syntax increase. For example, if you mis-specify a complex analysis and want to go back and rerun it with minor changes, or if you wish to repeat an analysis multiple times with minor variations, it is often more effi cient to write and edit the program code directly than to repeat point-and-click sequences. Finally, and perhaps most important, several elements of the SPSS command language, including several procedures covered in this manual, are available only via the Syntax Method. The question of which method is better learned fi rst, particularly in introductory statistics courses, is a diffi cult one on which knowledgeable and well-intentioned instructors can (and do) honestly disagree. Consequently, the book covers both methods. Thus, beginning users and course instructors can choose to focus on one or the other method—or both, in parallel or sequentially. In this edition, we have updated our latest book, A Simple Guide to SPSS: For Version 17.0 (Wadsworth, 2011) to include coverage of the most recent releases from SPSS, versions 18.0 & 19.0. Users of older versions of SPSS will fi nd one of our previous books appropriate for their respective version. Like the previous editions, this book is designed primarily to serve as an inexpensive companion volume to any standard introductory statistics text and for use in such a course. The types of analyses covered, as well as their sequence of presentation, are designed to parallel the sequence of topics covered in a typical introductory statistics course in psychology. However, the book should prove useful not only in other courses, but to fi rst-time users of SPSS in many other contexts as well. boxes to specify the kind of analysis desired, the variables involved, and