Practically every scientist uses statistics--from pharmacologists employing regression to understand the relation between the dose of a drug and its effects in the body, to agronomists using analysis of variance to test which fertilizer makes crops grow fastest. Thanks to VassarStats , created by psychologist Richard Lowry of Vassar College in Poughkeepsie, New York, anyone can now use the most popular statistical tests to analyze their data--free of charge.
Lowry began building Internet-based stats programs back in 1988 after growing "annoyed" with the cost of commercial software. His site offers an easy-to-use statistical package with bread-and-butter procedures such as linear regression, one-way and two-way analysis of variance, and the Mann-Whitney, chi-square, and t tests--as well as some more unusual procedures. Users can type in numbers or import data from a spreadsheet. The site also features simulations and demonstrations to teach statistical principles.
Indeed, Lowry strives to demystify the "magic rituals" behind the process. Instead of simply displaying a final P value--the odds of getting a significant result by chance if the experiment were repeated many times--the output includes intermediate results and offers cautions about possible misinterpretations. To find out more, novices and experts alike can page through Lowry's lucid 17-chapter Web textbook.