Displaying 20 results from an estimated 10000 matches similar to: "random effects in mixed model not that 'random'"
2011 Nov 24
4
I cannot get species scores to plot with site scores in MDS when I use a distance matrix as input. Problems with NA's?
Hi, First I should note I am relatively new to R so I would appreciate answers that take this into account.
I am trying to perform an MDS ordination using the function ?metaMDS? of the ?vegan? package. I want to ordinate species according to a set of functional traits. ?Species? here refers to ?sites? in traditional vegetation analyses while ?traits? here correspond to ?species? in such
2012 May 09
2
Random resampling of columns in species association matrices
I have a host-parasite association matrix in which parasite species are rows
and host species columns and cells contain the frequency of interactions.
Some parasites are associated with many hosts, and some hosts harbor several
parasites, and I want to repeatedly select only one single representative
host per "generalized" (multi-host) parasite to create a new matrix in which
no hosts
2012 Aug 24
3
Euclidean distance function
Hi,
I should preface this problem with a statement that although I am sure this
is a really easy function to write, I have tried and failed to get my head
around writing functions in R. I can use R where functions exist to do what
I want done, but have found myself completely incapable of writing them
myself.
The problem is that I have a table with several rows of species and several
columns of
2012 Sep 24
6
Script to count unique values from two linked matricies
I hope you can help with this one.
I have two matricies:
1. A species abundance matrix:
<http://r.789695.n4.nabble.com/file/n4643979/2species_matrix.jpg>
2. A species trait score matrix:
<http://r.789695.n4.nabble.com/file/n4643979/2trait_matrix.jpg>
The trait matrix lists trait scores for each species as listed in the
species abundance matrix.
I would like to create a script
2013 Apr 11
1
Ordination Plotting: Warning: Species scores not available
Hi,
I am working with a species-by-trait .csv file (columns=traits, rows=species) and get the following warning message when trying to plot results of both metaMDS and pcoa:
"Warning message:
In ordiplot(x, choices = choices, type = type, display = display, :
Species scores not available"
I am using a Gower's transformation in both procedures within the metaMDS or pcoa
2012 Dec 16
3
averaging X of specific Y (latitude)
Hello
I have a table describing butterfly range traits.
It is composed of three columns as below
Species name range size (X) latitude of range midpoint (Y)
There are 11 kinds of butterflies.
Each has its range size, and the latitude of each range midpoint ranges
from 9 to 19.
I would like to have the average range size of every degree of latitude.
For example, the average range
2005 Oct 26
2
AOV with repeated measures
Dear R user,
I have a question on using R to analyze data with repeated measurements. I
have 2 species with several strains (12) per species, each of which has
been measured twice with for a given trait. No particular covariance, just
two measures. Now I want to analyze the data with an ANOVA (aov)
considering these repeated measures to get the MSq and SSq for the species
and strain level. I
2007 May 11
1
Anova
Doea anyone know how to compute components of variance analysis? For example, I have the score of pupils on a test. Each pupil belongs to a school and within each school I may have several classes? How can I estimate the variance of the pupils, schools, classes and the errror variance?
Any examples?
Any help will be appreciated.
Jason
Dr. Iasonas Lamprianou
Department of Education
The
2007 Feb 13
1
Hierarchical ANOVA
Hello,
Does somebody could help me in the computation(formulation) of a
hierarchical ANOVA using linear model in R?
I'm working in a population biology study of an endangered species. My aim
is to see if I have effects of "Density of individuals/m2" on several
measured plants fitness traits.
As independent variables I have:
Humidity (continuous)
Nutritive substance (continuous)
2012 Dec 16
1
average X value of specific Y
Hello
I have a table describing butterfly range traits.
It is composed of three columns as below
Species name range size (X) latitude of range midpoint (Y)
There are 11 kinds of butterflies.
Each has its range size, and the latitude of each range midpoint ranges
from 9 to 19.
I would like to have the average range size of every degree of latitude.
For example, the average range
2012 Oct 01
1
lme help configuring random effects
Hi Everyone,
Sorry to ask what I think is a basic question but I really haven't found my answer yet in the archives.
I am trying to run a mixed effects model in R using the lme package. My experiment is such that I am interested in the effects of Temperature (2 levels) and Species (3 levels) on Growth. I collected individuals from three populations within each species. Because individuals
2011 Jan 06
3
Extract data
Dear List,
I have a data frame called trait with roughly 800 species in, each species have 15 columns of information:
Species 1 2 3 etc..
a t y h
b f j u
c r y u
etc..
I then have another data frame called com with the composition of species in each region, there are 506 different communities:
community species
NA1102 a
NA1102 c
NA0402 b
NA0402 c
AT1302 a
AT1302 b
etc..
What
2010 Oct 25
2
Mixed-effects model for overdispersed count data?
Hi,
I have to analyse the number of provisioning trips to nestlings according to a number of biological and environmental factors. I was thinking of building a mixed-effects model with species and nestid as random effects, using a Poisson distribution, but the data are overdispersed (variance/mean = 5). I then thought of using a mixed-effects model with negative binomial distribution, but I have
2012 Jun 15
1
How do anova() and Anova(type="III") handle incomplete designs?
Hello all:
I am confused about the output from a lm() model with an incomplete
design/missing level.
I have two categorical predictors and a continuous covariate (day) that
I am using to model larval mass (l.mass):
leaf.species has three levels - map, syc, and oak
cond.time has two levels - 30 and 150.
There are no response values for Map-150, so that entire, two-way, level
is missing.
2011 Jan 06
1
Multiple subsets of data
Dear List,
I have a data frame called trait with roughly 800 species in, each species have 15 columns of information:
Species 1 2 3 etc..
a t y h
b f j u
c r y u
etc..
I then have another data frame called com with the composition of species in each region, there are 506 different communities:
community species
NA1102 a
NA1102 c
NA0402 b
NA0402 c
AT1302 a
AT1302 b
etc..
What
2009 Aug 13
1
metafor random effects meta-analysis
Hello,
Great to see the new metafor package for meta-analysis.
I would like to perform a meta-analysis in which I initially calculate the intercept of the model with a nested random-effects structure. In lme, this would be
model<- lme(v3~1, random=~1|species/study, weights = varFixed(~Wt), method = "REML")
where multiple effects sizes are measured for some studies and more than
2010 Sep 22
3
extracting random effects from model formula
Hi R-users
I would like to extract the random effects ("1|SITE", "1+SPECIES|SITE"
and "BA|SITE") from this model formula:
Full_model <- formula (VAR ~ (1|SITE) + (1+SPECIES|SITE) + (BA|SITE) +
HEIGHT + COND + NN_DIST)
I tried:
terms(Full_model)
labels(terms(Full_model))
but I could not distinguish between random and fixed effects.
thanks
2019 Apr 05
0
new R packages for phylogenetic compartive methods
Dear all,
I wanted to let you know about four phylogenetic comparative methods (PCM) packages that have become available on (3 on CRAN and 1 on GitHub) recently that hopefully will be interesting to somebody. Three of them go significantly beyond the Brownian motion (BM) and Ornstein-Uhlenbeck (OU) processes.
1) There is a new version of mvSLOUCH available. The most important change is that
the
2019 Apr 05
0
new R packages for phylogenetic compartive methods
Dear all,
I wanted to let you know about four phylogenetic comparative methods (PCM) packages that have become available on (3 on CRAN and 1 on GitHub) recently that hopefully will be interesting to somebody. Three of them go significantly beyond the Brownian motion (BM) and Ornstein-Uhlenbeck (OU) processes.
1) There is a new version of mvSLOUCH available. The most important change is that
the
2012 Jun 26
1
How to estimate variance components with lmer for models with random effects and compare them with lme results
Hi,
I performed an experiment where I raised different families coming from two
different source populations, where each family was split up into a
different treatments. After the experiment I measured several traits on each
individual.
To test for an effect of either treatment or source as well as their
interaction, I used a linear mixed effect model with family as random
factor, i.e.