With the release of 4.02 and 4.0b, Prism now offers three normality tests, and I recommend that everyone switch to using the D’Agostino-Pearson omnibus test (rather than the Shapiro-Wilk or Kolmogorov-Smirnov tests). But before choosing a test, think about what you really learn by testing for normality. Normality tests are less useful than most scientists guess. This new short article explains why normality tests should be used with caution and why I recommend the D'Agostino-Pearson test.

The Prism viewer allows people who do not own Prism to view Prism files (created by any version of Prism). The Prism Viewer works just like Prism. It lets your colleagues examine and print all parts of your Prism files, including data, analysis results, info constants, and graphs. It also lets them study the choices (parameters) behind every analysis. But, of course, the Viewer cannot edit anything.

The Prism Viewer is free and will not expire. Both Mac and Windows versions are now available.

We are pleased to announce that StatMate 2 for WIndows and Macintosh is available now. We have completely revamped our sample-size and power program to make it easier to get the information you need and to make sound decisions regarding sample size and power.

Learn more about power and sample size calculations, and download the free 30-day demo, from www.graphpad.com/statmate.

If you use Prism 4, please update free to the latest releases. We've fixed some bugs and added some new features, including two new normality tests.

To update (and learn about the new features), go to www.graphpad.com/support and follow the update link on the lower left (which differs, depending on whether you use Prism Windows or Prism Mac).

Updating takes just a few minutes, and we strongly urge all Prism 4 users to do so.