On Tue, Apr 26, 2011 at 2:21 PM, Schatzi <adele_thomp...@cargill.com> wrote: > How do I extract the standard error of the parameter estimates? > > Also, if I would like to add two parameters together (x+y), can I use this > equation to calculate the new standard error?: > x = parameter 1 > y = parameter 2 > xSE = SE parameter 1 > ySE = SE parameter 2 > > NewSE=(x+y)*sqrt((xSE/x)^2+(ySE/y)^2)
Try taking the square roots of their variance: > example(nls) > sqrt(diag(vcov(fm1DNase1))) Asym xmid scal 0.07815395 0.08135321 0.03227080 > > # it gives the same result as another solution > # offered on this thread > coef(summary(fm1DNase1))[, "Std. Error"] Asym xmid scal 0.07815395 0.08135321 0.03227080 -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.