Simple Interactive Statistical Analysis (SISA), designed by a research consultant in the Netherlands, "allows you to do statistical analysis directly on the Internet." The program will calculate a variety of statistical procedures, including T-Tests, Poisson Distributions, and other calculations. The ability to perform analysis online provides users an opportunity to assess the software, which is also for sale. The Guide to Procedures provides helpful explanations of the different statistical procedures and guidelines for deciding on the appropriate procedure and filling out the calculation form. Numerous spreadsheets are also available to download.