On Sat, Feb 13, 2010 at 5:39 PM, Zoppoli, Gabriele (NIH/NCI) [G] <zoppolig at mail.nih.gov> wrote: > Please give me just a reference where I can find something useful. > To complement Sarah's suggestions, a good place to start is Quick-R [1]. Liviu [1] http://www.statmethods.net/stats/descriptives.html