R is GNU S, a system for statistical computation and graphics. It
consists of a language plus a run-time environment with graphics, a
debugger, access to certain system functions, and the ability to run
programs stored in script files.
The core of R is an interpreted computer language which allows
branching and looping as well as modular programming using functions.
The R distribution contains functionality for a large number of
statistical procedures such as: linear and generalized linear
models, nonlinear regression models, time series analysis, classical
parametric and nonparametric tests, clustering, smoothing and
graphical data representations. Additional modules ("add-on
packages") are available for a variety of specific purposes but are
not distributed with this package.