> > .(meanąSEM, ppb) ...that I don't understand. Standard error of the mean (SEM) is graphically explained at http://en.wikipedia.org/wiki/Standard_error_(statistics) -- Randy Oliver Grass Valley, CA www.ScientificBeekeeping.com *********************************************** The BEE-L mailing list is powered by L-Soft's renowned LISTSERV(R) list management software. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html Guidelines for posting to BEE-L can be found at: http://honeybeeworld.com/bee-l/guidelines.htm