Re: [R-sig-eco] Confidence intervals in lmer

2011-09-27 Thread Chris Howden
U could try the predict function with se.fit=true. I believe this should give u the predicted score and se and u can calculate CI from there. U'll have to create an input matrix with the score u want to predict for. Chris Howden Founding Partner Tricky Solutions Tricky Solutions 4 Tricky Problems

Re: [R-sig-eco] vegan rda

2011-09-27 Thread Sibylle Stöckli
Dear Jari, Thanks a lot for your very helpful comments. I still believe that my results are wrong using the 'standard' RDA code. Using the following code, I receive 'points' for the Y matrix (height) and arrows for the X matrix (species) (see pdf). It should be the opposite way (as seen i

Re: [R-sig-eco] vegan rda

2011-09-27 Thread Sibylle Stöckli
Dear Jari, Thanks a lot for your very helpful comments. I still believe that my results are wrong using the 'standard' RDA code. Using the following code, I receive 'points' for the Y matrix (height) and arrows for the X matrix (species) (see pdf). It should be the opposite way (as seen i

Re: [R-sig-eco] vegan rda

2011-09-27 Thread Jari Oksanen
Sibylle, I noticed that you also sent this message to the main R-news mailing list, but may not have received any answers. I'm not sure that I can answer to your questions either, since I don't quite follow your explanation. So here comes a rambling in a parallel universe in hope we go on with sim

Re: [R-sig-eco] Calculating spatial autocorrelation (Moran's I) when have zero-inflated data?

2011-09-27 Thread Gavin Simpson
On Sun, 2011-09-25 at 22:01 -0700, Laura S wrote: > Dear all: > > I was wondering if you have suggestions on how to analyze the spatial > autocorrelation of tree abundance in a grid of contiguous quadrats given > that the data set follows a zero inflated distribution, i.e., in many > quadrats the

Re: [R-sig-eco] "lack of fit" computation from LME model?

2011-09-27 Thread Gavin Simpson
Hi Laura, You might want to look at the lmmfit package: http://finzi.psych.upenn.edu/R/library/lmmfit/html/lmmfit-package.html which has several such measures (well, goodness of fit) for models with one grouping variable. You might get more traction on the R Mixed Models SIG. I often wonder (k

Re: [R-sig-eco] gam variable selection

2011-09-27 Thread Gavin Simpson
On Tue, 2011-09-27 at 14:40 +0200, Marco Helbich wrote: > thank you for clarifying. > so I can remove them all at once. Given their effects are already removed you could just work with the model *as is*. If you refit, you might have to be careful to ensure that the same model (and smooth complexit

[R-sig-eco] "lack of fit" computation from LME model?

2011-09-27 Thread L Quinn
Dear list, I recently submitted a paper in which I analyzed plant growth response to several environmental factors in several sites. I wanted to account for the variation attributable to the different sites, so I made "site" a random effect in a simple LME regression model (e.g. m<-lme(plantgr

[R-sig-eco] Confidence intervals in lmer

2011-09-27 Thread Adam Hayward
Dear list members, I have a significant interaction between two continuous variables (it happens to be a mixed model in lmer, but I imagine the same is applicable to a glm). The interaction tells me that the relationship between z and y changes as a function of x, but I want to know whether y has

Re: [R-sig-eco] gam variable selection

2011-09-27 Thread Marco Helbich
thank you for clarifying. so I can remove them all at once. best marco Am 27.09.2011 13:50, schrieb Gavin Simpson: On Tue, 2011-09-27 at 13:42 +0200, Marco Helbich wrote: Gavin, thank you for your reply, I appreciate it! After consulting the proposed paper, I have tried your suggestion setti

Re: [R-sig-eco] gam variable selection

2011-09-27 Thread Gavin Simpson
On Tue, 2011-09-27 at 13:42 +0200, Marco Helbich wrote: > Gavin, > > thank you for your reply, I appreciate it! > > After consulting the proposed paper, I have tried your suggestion > setting "select = T", which results again in another question: > > If the p-value is "NA" does this mean that t

Re: [R-sig-eco] gam variable selection

2011-09-27 Thread Marco Helbich
Gavin, thank you for your reply, I appreciate it! After consulting the proposed paper, I have tried your suggestion setting "select = T", which results again in another question: If the p-value is "NA" does this mean that the smoothing term is droped (or shrank to zero)? Independent of its h

Re: [R-sig-eco] gam variable selection

2011-09-27 Thread Gavin Simpson
On Tue, 2011-09-27 at 08:54 +0200, Marco Helbich wrote: > Dear list, > > I am studying the influence of several environmental factors (numeric & > dummies) on species densities (= numeric) using the gam() > function with a gaussian link function in the mgcv package. As stated in > Wood (2006) the