Re: Re: [R] gnls or nlme : how to obtain confidence intervals of fitted values

2004-10-05 Thread Rogers, James A [PGRD Groton]
vals for lme models. It is not easy to write such a function for the general case, but it may be relatively easy to write your own for special cases of lme models. Jim > Message: 9 > Date: Mon, 4 Oct 2004 21:42:20 +1000 > From: Andrew Robinson <[EMAIL PROTECTED]> > Subject:

Re: [R] gnls or nlme : how to obtain confidence intervals of fitted values

2004-10-04 Thread Andrew Robinson
The function estimable() from the gmodels part of the gregmisc package will do this, if applied appropriately. It allows for the estimation of arbitrary linear combinations of the parameter estimates of a model object, and calcualtes confidence intervals. I hope that this helps, Andrew On Tue

Re: [R] gnls or nlme : how to obtain confidence intervals of fitted values

2004-10-04 Thread David Scott
On Mon, 4 Oct 2004, Pierre MONTPIED wrote: Thanks Spencer but the intervals function gives confidence intervals of the parameters of the model not the predicted values. In the Soybean example it would be the CI of predicted weight for a given time, knowing all the parameters (Asym, xmid, scal, v

Re: [R] gnls or nlme : how to obtain confidence intervals of fitted values

2004-10-04 Thread Pierre MONTPIED
Thanks Spencer but the intervals function gives confidence intervals of the parameters of the model not the predicted values. In the Soybean example it would be the CI of predicted weight for a given time, knowing all the parameters (Asym, xmid, scal, variance function and residual) and their d

Re: [R] gnls or nlme : how to obtain confidence intervals of fitted values

2004-10-02 Thread Spencer Graves
Pinhiero and Bates (2000) Mixed-Effects Models in S and S-Plus (Springer) describe the use of "intervals" for that. In library(nlme), R 1.9.1 for Windows, I found documentation for intervals, intervals.gls, intervals.lme, intervals.lmList, and gnls. To an example in the documentation for

[R] gnls or nlme : how to obtain confidence intervals of fitted values

2004-10-01 Thread Pierre MONTPIED
Hi I use gnls to fit non linear models of the form y = alpha * x**beta (alpha and beta being linear functions of a 2nd regressor z i.e. alpha=a1+a2*z and beta=b1+b2*z) with variance function varPower(fitted(.)) which sounds correct for the data set I use. My purpose is to use the fitted models