Preface

While SAS and SPSS have many things in common, R is very different. My goal in writing this book is to help you translate what you know about SAS or SPSS into a working knowledge of R as quickly and easily as possible. I point out how they differ using terminology with which you are familiar, and show you which add-on packages will provide results most like those from SAS or SPSS. I provide many example programs done in SAS, SPSS, and R so that you can see how they compare topic by topic. When finished, you should know how to :

• Install R, choose a user interface, and choose and install add-on packages.
• Read data from various sources such as text or Excel files, SAS or SPSS data sets, or relational databases.
• Manage your data through transformations, recodes, and combining data sets from both the add-cases and add-variables approaches and restructuring data from wide to long formats and vice versa.
• Create publication-quality graphs including bar, histogram, pie, line, scatter, regression, box, error bar, and interaction plots.
• Perform the basic types of analyses to measure strength of association and group differences, and be able to know where to turn to learn how to do more complex methods.