These are free statistical calculating tools available on the Web through the grace of the individuals concerned. They are university sites, so they are a bit academic in their set-up and interface.

For a straitforward test of the significance of two proportions, visit the VassarStats page. Based on our research, VassarStats is one of the classiest stat tool sites on the Web. (The VassarStats page requires JavaScript; if your browser doesn't support it, use the page from IFA Services.)

For significance of two means, use the page from IFA Services. ( IFA Services has a good set of test pages.)

From www.physics.csbsju.edu in cyberspace comes a chi-square test.

We couldn't find an easy-to-use sample size calculator, so we made one of our own!

The herculean efforts put behind WebStat, a complete Java applet-based statistical anaylsis application, are commendable. This is one of the biggest programs offered for free on the Web. (It's also only for those intrepid among you who like to geek around with data and love stat programs, and have the patience for Java.)



Can't find your old statistics textbooks from your school days? Wouldn't want to crack them open even if you could? Fear not. For those needing a brush-up or a crash course in statistics, there are several online resources that will make learning or re-learning the subject more fun than burying your nose in a book.

David Stockburger of Southwest Missouri State University has published an online Introductory Statistics textbook which takes you step-by-step through all the major concepts and procedures. This is probably a good place to begin if you are fairly new to the topic.

HyperStat Online from Rice University is a well-put-together site divided into small bite-size chunks, with clear navigation and a glossary of terms that is constantly side-by-side with the text.

The "mother" of all online stat texts has got to be the Electronic Textbookfrom StatSoft. Going far beyond basic statistics, it covers multivariate methods as well. The whole thing can be downloaded to your computer for easier and faster reference.

From Ohio University comes some Animated Demonstrations of standard statistical formulas and calculations (should you still like to do them by hand!). Although a little hard to read (blue text on a black background), these animations are very cleverly put together.



We don't necessarily endorse any of these products, but for those who need statistical software, here are some of the more interesting options.

Inexpensive statistical test calculation software can be had from StatPac. This package has a more market researcher-friendly interface than the free stat test calculators on the Web and has many routine stat tests available for quick analysis.

Sort of a middle ground between free Java applets on the Web and a full-fledged statistical program, STATLETS is a trial-for-free, whole-program-for-fee Java application with a wide variety of statistical procedures.

Moving to industrial-strength software, perhaps the most interesting development in stat software circles is the way venerable SPSS has responded to the threat posed by recent upstarts in the marketplace. Having come a long way from its days of punched cards and mainframes, it recently bought Quantime, a strong presence in survey creation and data collection software. It has merged the two companies' products into an end-to-end market research package.

One of the principal "upstarts" in the stat software market has been Statistica, from StatSoft. For those who just love Windows (and the more windows the better) and who like to litter their PC desktops with rotating three-dimensional scatterplots, the amazing variety of techniques both in calculations and display of results appears to make this program a great value.



For those who are gluttons for things statistical, (or who are just interested), there are several compendiums of statistics links provided by individuals or organizations. If these sites don't have it, it probably doesn't exist. Number-crunchers' heaven!

Clay Helberg of SPPS, Inc. maintains a well-organized list of links called Statistics on the Web, with links to professional organizations, institutes, publications and publishers, software companies, as well as individual statisticians. Plus he has a rotating three-dimensional graphics chart to gaze at!

From CTI Statistics at the University of Glasgow (Scotland) comes Statistics Resources on the Web. For a look at what our statistical-minded colleagues in the UK are up to, this site is a place to start.

Hosted by the Department of Statistics at Carnegie Mellon University, StatLib is a sort of clearing house for distribution of data sets, software programs and extensions, etc.

From the University Florida Department of Statistics comes the Statistics Virtual Library. In addition to the usual listings, it sports a long list of Web sites of other university statistics departments (just in case you were wondering where your college statistics professor is hanging out these days.)