SISA is a collection of procedures to do simple interactive statistical calculations on the Internet. SISA is meant to give practitioners access to a variety of statistical tools for analysing the data they collect in their daily work. Medical Doctors, Engineers, Nurses, Social Workers, Valuators, Sociologists, Builders, Market researchers, and of course Statisticians too, are among those who can benefit from using this site.
There are the usual statistical procedures, but also some of the more unusual, but useful, ones. SISA is not meant to provide a full statistical package, including data manipulation, a number of good standard packages exist for that purpose. SISA is meant to operate on ready, aggregated type, data.
All procedures have been validated on Microsoft Explorer and Netscape Browsers. If you use another browser and have problems please give a precise description of the problem and where your Browser can be obtained.
Performance of the programs depends on your Browser. With some exact procedures you will run into limitations quite quickly which will show up as stack overflows, divisions by zero or your browser crashing in some other way. Exact procedures are often quite superior to approximations but can be demanding in terms of the required level of computing power. For the approximate procedures in general and using reasonable data for the exact procedures there is no evidence of the programs producing unreliable result. There have been few bug reports, if you think you found one do not hesitate to contact SISA. The pascal/Dos/Delphi programs are considerably more powerful and precise than the htm programs and you will see that you can stretch these programs very far for doing exact calculations.
Support is limited. This is not a commercial site, remember how much you paid for using this site. However, if your problem is specific to SISA and its use, give a good and clear description of your problem and maybe something can be done for you. Your email will mostly be answered, even if it is to say that there can be no help. But please, be patient.
All support is much appreciated. Make links to this site and tell your students or colleague's about it. If you have your own procedure to contribute, please do so. If you discover any errors in a text or program or if you have any other suggestions for improvements, making things better and more precise, please do not hesitate to contact SISA. You will be appropriately credited for your contribution.
SISA can support you to do your research and analysis. SISA's previous work has been concentrated in the U.K. and the Netherlands, however, we are happy to assist you with research anywhere in the world. Research organisation and preparation, data analysis, statistical analysis, report writing, literature reviews, judging third party research, statistical programming, analysis of existing data, are some of the possibilities. SISA's research experience is primarily concentrated in applied statistics, survey and opinion research, demography, epidemiology, health (services) research, health economics and health needs surveys. Recently also a number of projects were supported regarding domestic animals. Besides these areas we would be very interested to collaborate with you in other areas as required. Please contact SISA to discuss your requirements and possible collaboration and to inform about our competitive rates. Note that the answer to you first question will always be free! So don't hesitate to contact SISA to see what can be done for you.
Go here for reports on bugs, errors and changes
Go here for advice on how to cite SISA
And support SISA financially by making a donation here:
SISA online statistical analysis:
Daan Uitenbroek PhD
Research and Statistical Consultant