Hello, A newly-revised version of my introductory manual "The R Guide" is now available in the Contributed Documents section in CRAN. Among other changes, the description of the function t.test() has been expanded as well as an introduction to methods for the creation of prediction and confidence intervals with regression. The manual is still under 60 pages in length. The current version is 2.3. For those who attended/presented useR!2007 at Iowa State, thanks for making it a great conference. Jason -- Associate Professor of Statistics Mathematics and Computer Science Department University of Richmond, Virginia 23173 (804) 289-8081 fax:(804) 287-6664 http://www.mathcs.richmond.edu/~wowen "This is R. There is no if. Only how." Simon (Yoda) Blomberg