similar to: LINEAR MIXED EFFECT

Displaying 20 results from an estimated 110 matches similar to: "LINEAR MIXED EFFECT"

2009 Dec 04
0
pseudoreplication - LME
Need some help please I am trying to use this model because I have temporal replication in my data results<-read.table(file=file.choose(),header=T) attach(results) names(results) results<-na.omit(results) library(nlme) library(lattice) results<-groupedData(weight~date|group,outer=~diet,results) plot(results) plot(results,outer=T) model<-lme(weight~diet,random=~date|group,results)
2011 Feb 26
2
[R-sig-ME] Fwd: Re: ANOVA and Pseudoreplication in R
On 25/02/2011 21:22, Ben Ward wrote: > > -------- Original Message -------- > Subject: Re: [R] ANOVA and Pseudoreplication in R > Date: Fri, 25 Feb 2011 12:10:14 -0800 > From: Bert Gunter<gunter.berton at gene.com> > To: Ben Ward<benjamin.ward at bathspa.org> > CC: r-help<r-help at r-project.org> > > > > I can hopefully save bandwidth here by
2011 Feb 25
1
ANOVA and Pseudoreplication in R
Hi, As part of my dissertation, I'm going to be doing an Anova, comparing the "dead zone" diameters on plates of microbial growth with little paper disks "loaded" with antimicrobial, a clear zone appears where death occurs, the size depending on the strength and succeptibility. So it's basically 4 different treatments, and I'm comparing the diameters (in mm) of
2009 Apr 29
3
2 way ANOVA with possible pseudoreplication
Hi, I have an experiment with 2 independant factors which I have been trying to analyse in R. The problem is that there are several data points recorded on the same animal. However, no combination of treatments is repeated on the same animal. All possible combinations of treatments are done in a random order with as many points as possible being done on 1 animal before moving onto the next. The
2009 Apr 01
1
Help with mixed-effects model with temporal pseudoreplication!
Sorry if this is the wrong ml for this question, I am new to R. I am trying to use R to analyze the data from my thesis experiment and I am having troubles accounting for the pseudoreplication properly from having each participant repeat each treatment combination (combination of fixed factors) 5 times. The design of the experiment is as follows... Responses: CompletionTIme VisitedTargets
2009 Nov 09
1
Incomplete, unbalanced design, and pseudoreplication?
Hello, I am trying to help someone who has carried out an experiment and I'm finding it quite difficult to understand the appropriate model to use & code it. The response is a measurement - the amount of DNA extracted during the experiment. There were 2 factors to be tested - one is the condition under which the experiment took place and the other is the type of DNA to be
2011 Nov 18
1
cca with repeated measures
Dear all, How can I run a constrained correspondence analysis with the following data: 15 animals were measured repeatedly month-wise (over to 2 years) according to ther diet composition (8 food categories). our data.frame looks like this: food 1 2 ... 8 sex season year animal freq 12 8 ... 1 0 summer 2011 1 freq 0 7 ... 0 1 winter 2011 1 ... freq 0 7 ... 0 1 spring 2011 15 We
2003 Nov 06
1
Hierarchical glm
Hi all, I'm not sure how to correctly analyse the following data with glm, and hope for some advice from this list, ideally showing how to specify the model in R and perform the tests, and also for suggestions of literature. The data structure is like this: - 20 plant populations were investigated (random factor pop), which belong to different habitat types (factor ht) - Within
2002 Apr 15
1
Nested ANOVA with covariates
Dear All, I'm rather a beginner on nested ANOVAs, so here goes with my 2 questions; Qu 1: I'm modelling the number of galls on a leaf (the response variable) as a function of; the tree on which I find the leaf, the branch on which I find the leaf. Then, the tree and the branch are both random factors, and I'm quite happy that I should write; aov(galls~tree/branch +
2007 Nov 02
1
lme model with replicates within a random factor
Dear all, I wonder if anyone can help me with specifying a right model for my analysis. I am a beginner to lme methods. I was unfortunately not able to find a solution to my problem on my own. Data structure: I have sampled monthly 6 basins during two hydrological cycles, and I have taken several (2 to 4) samples (“replicate”) for each basin and month. I’m trying to relate Shannon diversity
2003 Apr 09
1
[OFF] Nested or not nested, this is the question.
Hi, sorry by this off. I'm still try to understand nested design. I have the follow example (fiction): I have 12 plots in 4 sizes in 3 replicates (4*3 = 12) In each plot I put 2 species (A and B) to reproduce. After a period I make samples in each board and count the number of individuals total (tot) and individuals A and B (nsp). Others individuals excepts A and B are in total of
2012 Feb 06
1
multiple comparisons in nested design
Dear professors and collegues I need to perform a analysis of dates from a nested experimental design. From "Bioestatical Analysis" of Zar "Bimetry of Sokal" & Rohlf "Design and Analysis of Experiments" of Montgomery I have: Sum (mean(x)_i - mean(x)_T)2 / (a-1) -> var(epsilon) + n sigma2_B + n b (sum alfa_i)2 / (a-1) Sum (mean(x)_ij - mean(x)_i)2 /
2010 Aug 19
1
GLMM random effects
Hello, I have a couple questions regarding generalized linear mixed models specifically around fitting the random effects terms correctly to account for any pseudo-replication. I am reading through and trying to follow examples from Zuur et al. Mixed Effects Models and Extensions in Ecology with R, but am still at bit unsure if I am specifying the models correctly. Background information: Our
2011 Apr 21
1
Accounting for overdispersion in a mixed-effect model with a proportion response variable and categorical explanatory variables.
Dear R-help-list, I have a problem in which the explanatory variables are categorical, the response variable is a proportion, and experiment contains technical replicates (pseudoreplicates) as well as biological replicated. I am new to both generalized linear models and mixed- effects models and would greatly appreciate the advice of experienced analysts in this matter. I analyzed the
2011 Feb 04
0
spatial autocorrelation for data that are temporally pseudoreplicated
Dear all, I collected my data from the different agricultural fields every week over a period of a month. how can I test for spatial autocorrelation in R with data that are temporally pseudoreplicated? I used lme with correlation=corCompSymm(form=~Date) to model temporal pseudoreplication. Regards, VG
2010 Oct 04
0
glmer or not - glmer model specification
Hello, I'm having some trouble figuring out the correct model specification for my data. The system consists of multiple populations of an organism, which have been genetically sampled for several years. The problem is this: A minority of individuals are found in more than one sample, either they have survived into the next sampling at the same location, or have migrated to another another
2008 May 26
0
use aov or lme for split plot design?
Dear all I'm not sure if I did the right analysis for my specific split splot design. We are studying biomass increase with different CO2 concentrations with four different functional plant groups (e.g. grasses, herbs, broad-leafed trees and conifers). Of each functional plant group we have four species. The design is orthogonal. The design is: Blocks: 2 (climate chambers, called
2006 Apr 16
0
[S] Problems with lme and 2 levels of nesting:Summary
I have taken the liberty of including the R-help mailing list on this reply as that is the appropriate place to discuss lmer results. On 4/5/06, Andreas Svensson <andreas.svensson at bio.ntnu.no> wrote: > Hello again > I have now recieved some helpful hints in this matter and will summarize them but first let me reiterate the problem: > > I had two treatments: 2 types of food
2010 Oct 25
3
question in using nlme and lme4 for unbalanced data
Hello: I have an two factorial random block design. It's a ecology experiment. My two factors are, guild removal and enfa removal. Both are two levels, 0 (no removal), 1 (removal). I have 5 blocks. But within each block, it's unbalanced at plot level because I have 5 plots instead of 4 in each block. Within each block, I have 1 plot with only guild removal, 1 plot with only enfa removal,
2011 May 19
1
lmer with 2 random effects with only two levels
Dear all, I am analysing a data set based on 6 groups of individuals. Each group is observed for 10 days. 5 days with one manipulation 5 days with another manipulation. I therefore have 6 replicate groups (n=6) each with one mean measurement for manipulation A and manipulation B. Each group consists of a set of males and females. An independent group of males for each group replicate, however