R is open source software for analyzing data and writing programs to create new ways of analyzing data. It is free and available for Windows, Apple, and Linux. R provides the same functionality as SAS, SPSS, Stata, and other commercial programs. In addition, new procedures or customized versions of analyses for specialized purposes are readily added. The basic R package provides a great deal of functionality that is extended by the availability of over 11,000 packages of functions.
GettingR.pdf provides information on how to install R on your computer with sections on Windows, Mac OS X, and Linux. If you are just beginning to use R, here are the Top 10 (actually 11) errors made by R beginners (Top10Errors.pdf).Â