R is the most amazing freeware to use for statistics, data mining and plotting!!!
As Wikipedia says:
R provides a wide variety of statistical and graphical techniques, including linear and nonlinear modeling, classical statistical tests, time-series analysis, classification, clustering, and others. R is easily extensible through functions and extensions, and the R community is noted for its active contributions in terms of packages. There are some important differences, but much code written for S runs unaltered. Many of R’s standard functions are written in R itself, which makes it easy for users to follow the algorithmic choices made. For computationally intensive tasks, C, C++, and Fortran code can be linked and called at run time. Advanced users can write C or Javacode to manipulate R objects directly.
…but I have to add:
If you don’t know the software and don’t have any programming / taping code notions, it might be a pain, at least for the first few days. However, it is worth getting over the adaptation time.
Here are some tips for you to get started:
Start, of course, by downloading the program on the Comprehensive R Archive Network (CRAN) page from the R website on the “Download, Packages” section.
And then I suggest you to read bits of the PDF “Introduction to R” provided by the CRAN as well. Unfortunately, the manual can be really soporific so I strongly encourage you to google your problems, even the most basics ones. The biggest advantage of using R (according to me) is that, in 80% of the case, someone in the world had the same (or similar) problem than you before. Often, just copying and pasting your code (even wrong, as long as it is not 20 lines long) on a search engine would provide a decent answer for your problem.
Let’s cite Wikipedia again:
“R community is noted for its active contributions in terms of packages”
is means that you can do pretty much everything with R. People all around the world are constantly creating new packages, functions, code for thousands and thousands of study-cases. Take advantage of the R community .