This tutorial offers a first introduction into R, which is an improved and freeware version of S. For most tasks, the freeware R and its commercial cousin S-Plus work in the same way and produce similar results. Most of the ideas in this tutorial apply to both R and S-Plus, although this document focuses on R in the interest of clarity.R is available as freeware from http://www.r-project.org, where one can also _nd a wealth of information and documentation.
This tutorial assumes that R is already properly installed on your computer. It is further assumed that the reader has some basic knowledge about statistics, equivalent to an introductory course in statistics. This tutorial introduces the R software for statistical analyses, and not the statistical analyses themselves. This tutorial occasionally mentions differences with SPSS, but the tutorial is also intended for novice users of statistical software.
One interesting property of R is that users can develop their own extensions, called packages, and distribute them to other users (similar to \extensions" for Mozilla web browsers). Packages may contain custom datasets, additional functions, re-formulations of existing functions, and more.
