similar to: difference between nls and nlme approaches

Hallo, yesterday I was puzzled when I discovered that I probabliy miss something in the interepretation of intercept in two-way lm models. I thought that the intercept, using the default contr.treatment contrasts, represents the mean of the group of observations having zero in all column of the model.matrix. It turns out not to be case To be more more clear I am attaching a short example:

Dear list, I'm currently trying to develop a model to assess clam yield potential in a lagoon. I'm using the zeroinfl function of the pscl package to fit a Zero-inflated negative binomial model, given the high occurrence of zero counts. I don't understand from the sentence in the pscl guide "Zero-inflated count models are a type of two-component mixture model, with a component

Dear R-list, I'm trying to estimate the relative importance of 6 environmental variables in determining clam yield. To estimate clam yield a previous work used the function Yield = (A^a*B^b*C^c...)^1/(a+b+c+...) where A,B,C... are the values of the environmental variables and the weights a,b,c... have not been calibrated on data but taken from literature. Now I'd like to estimate the

Dear R-Help Members, I am trying to read and analyse a set of 100 csv files. I need work only on some columns in each of those, so I decided to use a for loop, isolate the column in each file to work on, but then an error mesage appear: "undefined columns selected" Here is my code: setwd("F:/Data/") a<-list.files() for (x in a) { ? u<-read.csv(x, header=T,

Dear R-list, I have a statistical problem with the comparison of short time-series, representing densities of fish in different streams. For each stream (6 in total, here below showed only part of the dataset) I have 8 years of density data, as follows: year density stream 1 2000 0.51 stream1 2 2001 0.87 stream1 3 2002 0.68 stream1 4 2003 0.56 stream1 5 2004 0.50 stream1 6

Dear R-list, I have a statistical problem with the comparison of two short time-series of density data in an ecological framework. I have to compare two short time series (5 years, one value for each year) of species density data (it is the density of fish in two different streams) to test if the two means of the five densities are significantly different, so basically if the two mean

hello, i managed to get CI's for my curve - but now I need the intervall for a certain y point (y_tenth) of the curve.. can anyone help me with this? #####data: por<-data.frame(list(structure(list(run = structure(c(1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L), .Label = c("1", "3", "4"), class = "factor"), press = c(15, 21, 24, 29.5, 15, 21,

I wish to fit a dynamical model in R and I am running in a problem that requires some of your wisdom to solve. For SAS users I am searching for the equivalent of the retain statement. For people that want to read complicated explanations to help me: I have a system of two equations written as difference equations here. To boil it down. I have a dataframe with three variables y, X1, X2 which

Dear R-project team, I have a problem with the function varFixed() of the nlme-package. I used it with the squid-data of Zuur et. al 2009 (chapter 4), to fix increasing residuals (heterogenetiy) (see graph in the email) I get the message ' Variance function structure of class varFixed with no parameters, or uninitialized Could you help me please? Kind regards Franz

Hi, I would like to do a meta-analysis, i.e., a mixed-effects regression, but I don't seem to get what I want using both the nlme or metafor packages. My question: is there indeed no way to do it? And if so, is there another package I could use? Here are the details: In my meta-analysis I'm comparing different studies that report a measure at time zero and after a certain followup

Dear R-expert I'm fitting a non linear model (energy allocation model to individual growth data) using your nlme routine. For each individual I have thus a number of observations (age and size) to which I fit the nonlinear function, with random effects for the individuals on the estimated parameters (individual as the grouping factor). The sampling of these individuals was stratified (size

Yes but I need to encode at 2Kbps.. are there other free codecs expecially projected for very-low but rate? ---------- Original Message ---------------------------------- From: Jean-Marc Valin <Jean-Marc.Valin@USherbrooke.ca> Date: Tue, 30 May 2006 00:51:25 +1000 >Le lundi 29 mai 2006 ? 16:45 +0200, Leonardi Andrea a ?crit : >> Hi! >> Is it possible to encode at a rate of

I'm not sure, but I think that Microsoft have the license now.. anyone know if there is the source code to download? Or others codecs.. thank you very much ---------- Original Message ---------------------------------- From: "John Miles" <jmiles@pop.net> Date: Mon, 19 Jun 2006 10:15:59 -0700 >Do a search on "Voxware MetaVoice". I'm not sure who licenses

I'm sorry, but I've found in the paper "Speex: A Free Codec For Free Speech" at page 5 the phrase "If more than one channel is used, then an instance is required for each channel (Speex is not stateless)". What does it mean? Could it be that is the problem that I've met? Thanks Andrea ---------- Original Message ---------------------------------- From:

Hello list, I'm trying to fit a model like beta[trt]/(1+alpha*x) where the data include some grouping factor. The problem is that the estimate for alpha is undefined for some of the treatments - any value greater than 20 is equally good and a step function would suffice. Ignoring the grouping structure, I can fit this using nls with the port algorithm by restricting the upper value of alpha

Hello, I've been fitting a random effects model using nlme to some data, but I am discovering that the variation in my random effect is very small. As a result, I would like to replace it as a fixed effect (i.e. essentially fit the same model but with no random effect). As I understand it I could do this using nls(), but I'm using a number of options such as weights = varPower()

[[diverted from R-bugs to R-help by the list maintainer]] Dear Friend and distinguished R gurus, first of all really thank you very much for the marvellous tool that is R. I am using R 2.5.0, windows XP - italian language. I was perfoming some calculation on fractional exponential and I found a strange behaviour. I do not know if it is really a bug, but I would expect a different answer from

Hi all, I'm trying to use the PPL (Parma Polyhedra Library, bugseng.com/products/ppl) in one of my LLVM passes getting the error: > Error opening > '/home/jorge/SvnReps/Systems/llvm/build/Debug+Asserts/lib/MyAnalysis.so': > /home/jorge/SvnReps/Systems/llvm/build/Debug+Asserts/lib/MyAnalysis.so: > undefined symbol: _ZNK23Parma_Polyhedra_Library13PIP_Tree_Node2OKEv >

Hi Jorge, > I'm trying to use the PPL (Parma Polyhedra Library, > bugseng.com/products/ppl) in one of my LLVM passes getting the error: > >> Error opening >> '/home/jorge/SvnReps/Systems/llvm/build/Debug+Asserts/lib/MyAnalysis.so': >> /home/jorge/SvnReps/Systems/llvm/build/Debug+Asserts/lib/MyAnalysis.so: >> undefined symbol:

Greetings- I am in the process of constructing a nonlinear model using nlme. The model is attempting to fit a nested data structure from some public-opinion data (the data are from individuals nested within organizations). The question I have is fairly simple (I hope). The data were collected in two stages: a 15,000-subject randomly-sampled telephone interview (the SCREEN), with 2,517 subjects