Tutorial spss

Introduction to SPSS

Written by:

Emory Morrison

Center for Social Science Computation & Research 145 Savery Hall University of Washington Seattle WA 98195 U.S.A. (206)543-8110

October 99
http://augustus.csscr.washington.edu/pdf/spss.pdf

CSSCR SPSS 10/19/99 EM Page 1 of 14

INTRODUCTION

TO

SPSS

SPSS (Statistical Package for the Social Sciences) is a versatile softwarepackage which primarily assists users in performing complex statistical analyses of quantitative data sets. The software allows users to create, modify, and analyze data, as well as to produce graphics to display findings in reports or presentations. SPSS is comparable to other general statistical analysis software such as SAS, Stata, or S-Plus. Relative to these other software packages, SPSS iseasier to learn and more simple to use. However, it is more restrictive than the other statistics packages; advanced users have a tougher time tailoring SPSS to meet their specialized analytical needs. This document should help new users get started in SPSS. It is structured in question and answer format, and addresses in a logical sequence the questions that a new user might have. Once you are onyour way, (or if you already have a basic knowledge of SPSS), you can use the set of manuals that SPSS provides, the help features within SPSS, or run the SPSS on-line tutorial for more comprehensive guidance. Please note, at the time of the writing of this document, CSSCR is using version 9.0 of SPSS software. All information in this document will pertain to SPSS version 9.0.

How do I startusing SPSS at CSSCR?
SPSS (version 9.0) is on all the PCs in CSSCR. The process of launching the software is the same as for any other frequently used package in the lab. At the initial window (once Windows has been launched) find the SPSS icon. Double click with your mouse, and voila. This screen is the data editor window in SPSS. It is one of a seven basic windows that SPSS provides (other windowsinclude: the output viewer, syntax editor, chart editor, pivot table editor, text output editor, and script editor). The data editor window is the most fundamental. With the exception of the more advanced syntactical procedures, you must enter data in the data editor window before SPSS can perform any operations.

Figure 1

CSSCR SPSS 10/19/99 EM Page 1 of 15http://augustus.csscr.washington.edu/pdf/spss.pdf

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What Are Data?
SPSS is very restrictive in what it recognizes as data. For SPSS, data are members drawn from a similar set (cases), that are each described by the same set of features (variables). Cases are listed in rows, and variables are listed along columns. The block where a row and column intersect is known as a cell. Each cellcontains the value on the variable (the column) for the case (the row). Thus, data must take the form of a spreadsheet. An illustration of data in the SPSS data editor window is presented below.

Figure 2

In Figure 2, the cases are countries of the world (thirteen of which appear in the figure) and the variables are characteristics of each of the countries (i.e. population, population density,percent of population residing in urban regions, etc.). Since SPSS only recognizes a variable title eight characters long, many of the variables have shortened names. For example, the column that contains information on population is titled populatn. The value for the case Australia for the variable ÒpopulatnÓ is 17800 (which, since the units are in thousands, indicates that Australia has apopulation of 17.8 million people). The value for the case Afghanistan for the variable religion is Muslim. Values can either be numeric or in character (also known as string) format. However, if you want to use a variable in an analysis, you will need to code it in numeric format (even if a character format makes more sense to you). So, if you want to analyze the relationship between population size...