similar to: lme problem

Dear R-users: I have some problems working with lme function, and i would be glad if anyone could help me. this kind of analysis i was used to do with PROC MIXED from SAS, but i would like to move to R, for many reasons... So, the problem is: Imagine the I have 3 factors: fact_A, fact_B and fact_C: The latter I would assume that is random, and the rest of them are fixed. Analysing the

Hello I am trying to fit a REML to some soil mineral data which has been collected over the time period 1999 - 2004. I want to know if the 19 different treatments imposed, differ in terms of their soil mineral content. A tree model of the data has shown differences between the treatments can be attributed to the Magnesium, Potassium and organic matter content of the soil, with Magnesium being the

I am trying to extract into a scalar the value of Phi from the printed output of gls or lme using corAR1 correlation. ie I want the estimate of the autocorrelation. I can't see how to do this and haven't seen it anywhere in str(model.lme). I can get all the other information - fixed and random effects etc. Is there an obvious way so that I can save the brick wall some damage? TIA

Dear R-users, I'm currently having trouble with the implementation of a groupedData object in the lme() function. Executing the following function > applyScalingSimp <- function(input.population) > { > ## GA is a time value > varInOrder <- c("GA","weight","grouping","sex") > modelVar <-

Dear R-users, I am a newbie to this site and a relative new-comer to S/R, so please tread lightly, for you tread... There have been several posting relating to problems with augPred() from the nlme library. Here is a "fix" for one of these problems which may lie at the root of others. In my case the problem with augPred() lay in gsummary(), which augPred() uses, causing it to fail.

Windows Vista R 2.10.1 Does the following use of groupedData and lme produce an analysis with both random intercept and slope, or only random slope? zz<-groupedData(y~time | Subject,data=data.frame(data), labels = list( x = "Time", y = "y" ), units = list( x = "(yr)", y = "(mm)") ) plot(zz)

I am trying to do a repeated measurement anova using an lme. I have the following variables: -ID, the identification of the individual -trail, with 2 levels -treatment, with 3 -time, measure 5 times the same individual -VCL, the response variable I tried the following in R, within.gr<-groupedData(VCL~time|ID/treatment/time,data=within)

I am trying to extract the solution from a simple lme calculation. For example (the first 4 have a mean 0, sd 1): > y<-c(-1.118,-.5,.5,1.118,10) > gp<-factor(c(rep('one',4),'two')) > res<-lme(y~1,rand=~1|gp) Linear mixed-effects model fit by REML Data: NULL Log-restricted-likelihood: -8.67141 Fixed: y ~ 1 (Intercept) 4.962502 Random effects:

I'm trying to understand better the differences between fixed and random effects by running very simple examples in the nlme package. My first attempt was to try doing a t-test in lme. This is very similar to the Rail example that comes with nlme, but it has two groups instead of five. So I try a1 <- 1:10 a2 <- 7:16 t.test(a2,a1) getting t(18)=4.43, p=.0003224. Then I try to do it

Using Version 0.64.1 (May 8, 1999) Hi, Last time I used a stats package it was SAS so I have been struggling with the paradigm shift to R in particular the syntax for using lme (linear mixed effects model). My data relates to growth data and is set up with vectors for ID, several explanatory variables and the response variable. In contrast, the data object used in the lme examples, ie.

Hello there, I am using the 'nlme' package to analyse among group and in between group variances. I do struggle a little using the respective plot-functions. I created a grouped object: group.lme <- groupedData(obsday ~ oro | id, data=read.table("data-lme.txt", header=T), labels=list(x = "Day of Year", y = "ID number")) When I plot, however

Hi all! I am working on a nested lme model with one fixed effect ("treatment", which 3 levels) and two random effects for "Individuals" (four of them) within "treatment" and "replicate -2 levels-" within "individual" within "treatment". For doing so, I´ve been trying to create a factor for Individual%in%Treatment, say IT by

Dear R-Community! For example I have a study with 4 treatment groups (10 subjects per group) and 4 visits. Additionally, the gender is taken into account. I think - and hope this is a goog idea (!) - this data can be analysed using lme as below. In a balanced design everything is fine, but in an unbalanced design there are differences depending on fitting y~visit*treat*gender or

I'm trying to set up a mixed model to solve using lme. It will have 3 fixed effects, two random effects and two interaction terms. I've been reading Pinheiro's and Bates's book on the nmle library, but find the part about display functions to be unclear. When creating a groupedData object from a data.frame, you need to enter a function of the form: response ~primary|grouping

Dear all,   I have data from the following experimental design and trying to fit a mixed model with lme function according to following steps but struggling. Any help is deeply appreciated.   1) Experimental design: I have 40 plants each of which has 4 clones. Each clone planted to one of 4 blocks. Phenotypes were collected from each clone for 3 consecutive years. I have genotypes of plants. I

Dear R-users, I am trying to analyse the data of the box 10.5 in the Biometry from Sokal and Rohlf (2001) using R. This is a three-level nested anova with equal sample size : 3 different treatments are compared ; 2 rats (coded 1 or 2) / treatment are studied ; 3 preparations (coded 1, 2 or 3) / rats are available ; 2 readings of the glycogen content / preparations are realised. Treatment is

Hi, this is my first time using the nlme package, and I ran into the following puzzling problem. I estimated a mixed effects model using lme, once using groupedData, once explicitly stating the equations. I had the following outputs. All the coefficients were similar, but they're always slightly different, making me think that it's not due to numerical error. Also, what is the

Hello, I have an unbalanced mixed model design with two fixed effects "site" (2 levels) and "timeOfDay" (4 levels) and two random effects "day" (3 consecutive days) and "trap" (6 unique traps, 3 per site). The dependent variable is the body length ("BL") of insect larvae from 7 to 29 individuals per trap (104 individuals in total). To account

Hi, all, I have a question about random effects model. I am dealing with a three-factor experiment dataset. The response variable y is modeled against three factors: Samples, Operators, and Runs. The experimental design is as follow: 4 samples were randomly chosen from a large pool of test samples. Each of the 4 samples was analyzed by 4 operators, randomly selected from a group of

Hello, I have a dataset concerning slugs. For each slug, the number of pumps per one time slot was counted. The number of pumps follows Bi(30, p) where p is very small, thus could be approximated by Poisson dist. (# of pumps is very often = 0) The slugs were observed during 12 time slots which are correlated in time as AR(1). The time slots are divided into two categories: Resting time