Some of you may not know of the GNU Open-Source project (free) statistic software suite simply called "R". Unlike SPSS which runs in a slow JavaVM environment, and SAS which does run on Mac OS at all, R exists exists for Mac OS X, Linux, and Windows. If you're up for it, even the source code is also available for download and compilation or modification. To download the software, here is a link to a Canadian "mirror" site hosted at Dalhousie University: http://mirror.its.dal.ca/cran/
What is "R": R is an integrated suite of software facilities for data manipulation, calculation and graphical display. It includes
• an effective data handling and storage facility, • a suite of operators for calculations on arrays, in particular matrices, • a large, coherent, integrated collection of intermediate tools for data analysis, • graphical facilities for data analysis and display either on-screen or on hardcopy, and • a well-developed, simple and effective programming language which includes conditionals, loops, user-defined recursive functions and input and output facilities.
Here is the main page for the R-project: http://www.r-project.org/
I also found this journal article of interest, which some in this group may find of interest "Transitioning to R: Replicating SAS, Stata, and SUDAAN Analysis Techniques in Health Policy Data" http://journal.R-project.org/archive/2009-2/RJournal_2009-2_Damico.pdf
The "R" FAQ can be found here, http://mirror.its.dal.ca/cran/