On Feb 1, 2010, at 12:37 PM, Антон Морковин wrote: > Dear all, > what function can be used to calculate weighted SD or/and SE¿ > > There's no such stuff in 'base' package. Seems as though lm with a weights argument could be used fairly simply. > > Best regards, > A.A.Morkovin David Winsemius, MD Heritage Laboratories West Hartford, CT