Would a free epidemiological software tool be useful for your work? Then you might want to check out these three.
Epi Info is a free program from the CDC that allows the creation of data entry systems and the analysis of data. Version 7 can be copied into a Windows-based computer and can also be run from a flash drive. Epi Info is flexible and scalable, and was designed with epidemiologists and other public health workers lacking a background in information technology in mind.
OpenEpi provides a number of epidemiologic and statistical tools for summary data. OpenEpi can be run in browsers such as Microsoft Internet Explorer, Mozilla Firefox, Safari, and Chrome. OpenEpi provides statistics for counts and measurements in descriptive and analytic studies, stratified analysis with exact confidence limits, matched pair and person-time analysis, sample size and power calculations, random numbers, sensitivity, specificity and other evaluation statistics, R x C tables, and chi-square for dose-response.
WinPepi consists of a set of Windows-based programs that provide most of the statistical procedures commonly used in the planning and analysis of epidemiological studies. These programs can be run from a flash drive.
You can read more about these at epimonitor.
In addition, you may also be interested in perusing the Wikipedia article Comparison of Statistical Packages.