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Departments: Quality Software

Software Review

SigmaStat 3.0

Statistics software for the nonstatistician

by Felix Grant

SPSS has a long and honorable history in the world of statistics but does not have a reputation for offering no-brainer solutions to the statistically terrified. Through numerous acquisitions, the company gradually acquired several user-friendly packages, but these always sat awkwardly with its high-end core business. That conflict recently came to an end when the entity formerly known as SPSS Science moved to Systat Software International--with the Sigma product line being the advance party.

If you’re one of the many quality professionals who smile bravely and pop aspirin like candy when statistics are required, then SigmaStat is right up your alley. Few other packages offer a smoother entry, shorter learning curve and less pain for the reluctant statistician.

To start, there’s the contextual prompter. For example, if you’ve attempted a t test on unsuitable data that fails the normality test, most stats packages will give you a meaningless answer or an error report. Not SigmaStat--it mentions the problem, then immediately asks if you would like to run a Mann-Whitney rank sum test instead. Once you’ve agreed, you get a Mann-Whitney result, helpful background information and a plain-English explanation of what it means, all presented in a neat, clear, rich-text report ready for printing on a half-sheet of paper. Better still, there is another equally helpful half-sheet explaining why that t-test wasn’t a good idea, so you can confidently explain your change of plan to colleagues.

What could be better? Well, the entire package is this good.

You won’t, for instance, have reached that attempt on a t test unaided. The “Statistics” menu, instead of the usual maze of statspeak, is organized along task-oriented lines. Tests are organized by tasks you might want to perform. Pick from headings like “Describe Data,” “Compare Two Groups” or “Before and After.” This doesn’t suggest that you’ll never have to do anything; eventually you’ll have to come against the nitty-gritty. But at least you’ll arrive at the task through sensible guidance, with helpful advice at your side and an appropriately selected toolkit on hand.

That toolkit contains everything you’re likely to need for day-to-day use in a real-life working quality environment, from basic descriptives through tests, curve fitting, and a good survival analysis implementation, all of which are fast and sleek. Transforms--like Excel formulae, but dedicated to the needs of statistical work and applied automatically to a column without any need to copy and paste--are fast, effective and easy-to-use. Transforming installation and failure dates into a full component survival analysis report takes approximately eight mouse clicks.

The reports are page-formatted in U.S. letter shape by default, but you can change that at will. Users on the metric system can choose millimeters instead of centimeters or the default, inches. Page formatting doesn’t have to include paper: PDF and HTML are available. There are also ruler bars at the top, plus common word processor functions such as decimal-aligned tabs, search and replace, go-to, and date and time fields. And for more advanced report preparation, moving the results into a word processor or DTP is a snap.

Working with other programs is provided for. SigmaStat opens a useful range of other file formats directly, imports from still more (including Microsoft Access) and exports to a spread of generic ones. Graphs, like statistical methods, are handled much better by SigmaStat than by Excel. Simple point-and-clicks result in selective subranges, comparative multiple plots, true histograms and much more.

The program has its own dedicated native statistical data worksheet. Although many users might prefer to stick with Excel (You can, of course, import your Excel data), you should consider the methodological advantages of using SigmaStat’s own sheet--well-designed, statistically aware and, at 32 million rows by 32,000 columns, offering much greater process capacity.

All in all, it’s an ideal package for the day-to-day needs of a busy professional for whom stats are a necessary tool, not a major area of expertise. Author and academic Derek Rowntree famously said that he couldn’t offer statistics without effort, but he could offer statistics without tears. SigmaStat can make the same promise.

About the author
Felix Grant is a lecturer and research consultant in the United Kingdom.

by Systat

Requirements: Windows 98, 2000, NT 4.0 or XP; Pentium 200 MHz or higher

Price: $599. Government and academic pricing available


  • Systat Software Inc.
  • 501 Canal Blvd., Ste. C
  • Point Richmond, CA 94804
  • Phone: (800) 797-7401
  • Fax: (510) 231-4789
  • E-mail: sales@systat.com
  • www.systat.com