Displaying 20 results from an estimated 100 matches similar to: "anova on binomial LMER objects"
2006 Feb 09
1
glmm.admb - bug and possible solution??
Dear Dr Skaug and R users,
just discovered glmm.admb in R, and it seems a very useful tool.
However, I ran into a problem when I compare two models:
m1<-glmm.admb(survival~light*species*damage, random=~1, group="table",
data=bm, family="binomial", link="logit")
m1.1<-glmm.admb(survival~(light+species+damage)^2, random=~1,
group="table", data=bm,
2006 Sep 12
1
Using XY location data to calculate ecological parameters
Dear R gurus,
I have XY data giving the locations of tree seedlings that were
surveyed during a 210 meter belt transect. This belt transect was
taken by stretching a line across the field, then measuring all
seedlings within 1 meter on either side of the line. The end result
was XY coordinates and height for ~1,300 seedlings. I would like to
use that data to calculate density of
2003 Nov 04
1
glm offset and interaction bugs (PR#4941)
Full_Name: Charles J. Geyer
Version: 1.8.0
OS: i686-pc-linux-gnu (Suse 8.2)
Submission from: (NULL) (134.84.86.22)
Two bugs (perhaps related, perhaps independent) revealed by the same
Poisson regression with offset
mydata <- read.table(url("http://www.stat.umn.edu/geyer/5931/mle/seeds.txt"))
out.fubar <- glm(seedlings ~ burn01 + vegtype * burn02 +
offset(log(totalseeds)),
2006 Apr 23
1
Comparing GLMMs and GLMs with quasi-binomial errors?
Dear All,
I am analysing a dataset on levels of herbivory in seedlings in an
experimental setup in a rainforest.
I have seven classes/categories of seedling damage/herbivory that I want to
analyse, modelling each separately.
There are twenty maternal trees, with eight groups of seedlings around each.
Each tree has a TreeID, which I use as the random effect (blocking factor).
There are two
2009 Aug 31
2
interactions and stall or memory shortage
Hello,
After putting together interaction code that worked for a single pair of
interactions, when I try to evaluate two pairs of interactions(
flowers*gopher, flowers*rockiness) my computer runs out of memory, and the
larger desktop I use just doesn't go anywhere after about 20 minutes.
Is it really that big a calculation?
to start:
mle2(minuslogl = Lily_sum$seedlings ~ dnbinom(mu = a,
2008 May 15
2
mixed effects models with nested factors
Hi everybody,
I am trying to fit a model with the lmer function for mixed effects. I have an experimental design consisting of 5 field plots. Each plot is divided in 12 subplots where the influence of three factors on the growing of tree seedlings is tested: (1) seed (1 = presence; 0 = absence); (2) seedling species (oak holm vs. pine); (3) treatment (three different treatments). In each of
2011 Jun 28
2
coxph() - unexpected result using Crawley's seedlings data (The R Book)
Hi,
I ran the example on pp. 799-800 from Machael Crawley's "The R Book" using package survival v. 2.36-5, R 2.13.0 and RStudio 0.94.83. The model is a Cox's Proportional Hazards model. The result was quite different compared to the R Book. I have compared my code to the code in the book but can not find any differences in the function call. My results are attached as well as a
2009 Aug 28
1
Help with glmer {lme4) function: how to return F or t statistics instead of z statistics.
Hi,
I'm new to R and GLMMs, and I've been unable to find the answers to my
questions by trawling through the R help archives. I'm hoping someone
here can help me.
I'm running an analysis on Seedling survival (count data=Poisson
distribution) on restoration sites, and my main interest is in
determining whether the Nutrients (N) and water absorbing polymer Gel
(G) additions to the
2005 Jul 19
2
Regression lines for differently-sized groups on the same plot
Hi there,
I've looked through the very helpful advice about adding fitted lines to
plots in the r-help archive, and can't find a post where someone has offered
a solution for my specific problem. I need to plot logistic regression fits
from three differently-sized data subsets on a plot of the entire dataset.
A description and code are below:
I have an unbalanced dataset
2011 Apr 10
1
survival object
Hi All,
I am trying to do a survivorship analysis with library(survival)from a data
set that looks like this:
I followed a bunch of naturally germinated seedlings of an annual plant from
germination to death (none made it to reproduce, and died in a period of ~60
days after germination.)
I also know the size of the seed of every individual censused. So I am
trying to analyze seedling survival as
1999 Sep 27
0
HTML Output from R
Apologies to the group for not having summarized (and taking all this time)
all the replies I got on this topic.
The original question was if anyone had done HTML output from R. The
message also included a first attempt at writing such a function..
_________
Thanks, to Terry Westley who suggested that I model the function after
write.table. I was not aware of write.table (my fault). Since then I
2009 Sep 26
1
Multiple comparisons for coxph survival analysis model
Hello, all R-users!
I am working on fitting a survival analysis model using the coxph
function for Cox proportional hazards regression model. Data look like
usual:
==========================
group block death censor
Group1 1 4 1
Group1 1 12 1
...
Group2 30 4 1
Group2 30 4 1
...
Group3 57 16
2010 Apr 20
1
multiple plots problem
hello,
i try to plot 3 graphs which have the same x.axis underneath each other. i'd
like the plots to be aligned without margings between the boxes and draw a
single x axis beneath the lowest plot.
i managed to get the alignment by setting par(mar), but the middle box is
stretched
and i cant't figure out how to get around this. par(pin) was my guess, but
this doesn't do the job
2013 Oct 03
2
SSweibull() : problems with step factor and singular gradient
SSweibull() : problems with step factor and singular gradient
Hello
I am working with growth data of ~4000 tree seedlings and trying to fit non-linear Weibull growth curves through the data of each plant. Since they differ a lot in their shape, initial parameters cannot be set for all plants. That’s why I use the self-starting function SSweibull().
However, I often got two error messages:
2009 Aug 28
0
Help with glmer {lme4} function: how to return F or t statistics instead of z statistics?
Hi,
I'm new to R and GLMMs, and I've been unable to find the answers to my
questions by trawling through the R help archives. I'm hoping someone
here can help me.
I'm running an analysis on Seedling survival (count data=Poisson
distribution) on restoration sites, and my main interest is in
determining whether the Nutrients (N) and water absorbing polymer Gel
(G) additions to the
2009 Oct 05
1
interpreting glmer results
Hi all,
I am trying to run a glm with mixed effects. My response variable is
number of seedlings emerging; my fixed effects are the tree species
and distance from the tree (in two classes - near and far).; my random
effect is the individual tree itself (here called Plot). The command
I've used is:
mod <- glmer(number ~ Species + distance + offset(area) + (1|Plot),
family = poisson)
2012 Jul 31
0
Arrangement of names
Dear R-help members
I would be grateful if anyone could help me with the following problem:
1: I changed the font style of the plant names (along x-axis, under the bars) to "italic" . How can I avoid that the font in the legend also changes to "italic"?
2. I would like to place the plant names (along x-axis, under the bars) in a way that :
a) the first plant name is under the
1999 Feb 12
1
Fisher's Exact Test
Appology in advance if this has been asked and answered. I am getting different
answers using Fisher's exact test in the package ctest. For example:
x_cbind(c(8, 22), c(31, 29))
fisher.test(x)
Fisher's Exact Test for Count Data
data: x
p-value = 0.04024
alternative hypothesis: two.sided
However, in SAS or other packages on the net the answer I get is p-value=
0.02664.
Is this
2008 Feb 22
3
projection.matrix() {popbio} for more than one matrix
Hello,
I am trying to use the projection.matrix( ) function and am following the
example given. I have my data formatted very similar to the test.census
example.
> str(AsMi05mat)
`data.frame': 1854 obs. of 6 variables:
$ Tag : num 501 502 503 504 505 506 507 508 509 510 ...
$ Year : int 1995 1995 1995 1995 1995 1995 1995 1995 1995 1995 ...
$ Length : num 34
2009 Nov 13
0
z-test with NAs
Dear all
I am learning R
I am doing Z-test with package 'BSDA'
here is my syntax and result:
> sdgr.ztest<-z.test(growth[type=='SD'& from_treeline=='above'], + growth[type=='SD'& from_treeline=='below'],alternative = "two.sided", + mu = 0, sigma.x =(sd(growth[type=='SD'& from_treeline=='above'],na.rm = T)), +