I need some free/cheap software for data analysis with a very large data sets (~500,000 observations). I need to be able to merge two such large files. I will be using correlations, regression and survival analysis. If possible I may also play with some neural networks. Any advice where I can look to find something like this? ================================================================= Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =================================================================