Open Source Tools for Data Mining
I have been asked what my favorite  Open Source Tools for Data Mining with Statistics support  are.  In no particular order, other than recall, here they are.  Feel free to comment on these or any others you like that fall into this same category and the reasons why :   R - http://r-project.org/   GGobi - http://www.ggobi.org  - a visualization program for R   Mondrain - http://stats.math.uni-augsburg.de/Mondrian  - a visualization program for R (more biased for category work)   KNIME - http://www.knime.org   Orange - http://orange.biolab.si   Tanagra - http://eric.univ-lyon2.fr/~ricco/tanagra   Weka - http://www.cs.waikato.ac.nz/ml/weka   Yale / RapidMiner - http://rapid-i.com   Enjoy!  -Thad