Displaying 20 results from an estimated 400 matches similar to: "hierarchical gamma model in lme4"
2011 May 18
0
using hglm to fit a gamma GLMM with nested random effects?
Apologies for continuing to ask about this but . . in my quest to fit a
gamma GLMM model to my data (see partial copy of thread below), I'm
exploring using hglm today. The question of the day has to do with the
errors I'm currently getting from the hglm package. Can hglm handle a model
with nested random effects? I don't see an example of one of those in the
package documentation. If
2011 May 13
1
using glmer to fit a mixed-effects model with gamma-distributed response variable
Sub: using glmer to fit a mixed-effects model with gamma-distributed
response variable
Hello,
I'm currently trying to fit a mixed effects model , i.e.:
> burnedmodel1.2<-glmer(gpost.f.crwn.length~lg.shigo.av+dbh+leaf.area+
bark.thick.bh+ht.any+ht.alive+(1|site/transect/plot), family=gaussian,
na.action=na.omit, data=rws30.BL)
If I run this code, I get the error below:
Error:
2011 Apr 28
1
using lme4 with three nested random effects
Hi all,
I'm trying to fit models for data with three levels of nested random
effects: site/transect/plot. For example,
modelincrBS<-glmer(l.ru.ba.incr~shigo.av+pre.f.crwn.length+bark.thick.bh+Date+slope.pos.num+dens.T+dbh+leaf.area+can.pos.num+(1|site/transect/plot),
data=rws30.UL, family=gaussian, na.action=na.omit)
but I get the following error:
Error: length(f1) == length(f2) is not
2011 May 13
1
graphs of gamma, normal fit to a histogram are about half as large as they should be
Hello,
I'm trying to compare the fit of two distributions, normal and gamma, to a
histogram of my response variable.
rate<-mean(na.omit(rwb$post.f.crwn.length))/var(na.omit(rwb$post.f.crwn.length))
shape<-rate*mean(na.omit(rwb$post.f.crwn.length))
hist((rwb$post.f.crwn.length), main="rwb$post.f.crwn.length")
2007 Oct 23
1
Multivariate regression tree: problems with surrogate splits
R helpers,
I am working with the R program performing multivariate regression trees (MRT). I have a matrix with species and environmental variables saved as a CSV file (sprot_matrix.csv), I have 42 species and 8 environmental variables (SECCHI+PH+TA+PTOT+NTOT+CHLA+AREA+ MEANDEP) for 104 samples
Title
SpA
SpB
SpC
SpD
Varible1
Variable2
Variable3
Sample1
Sample 2
2011 Nov 12
1
Subsetting data leads to funky plots
I'm trying out a basic plot, but something about the way I subset my data
leads to problems with the plot.
Here is the first bit of my data set
year,date,location,quadrat_juvenile,photo_location,photo_exists,genus,count,divers
2005,2005-04-30, 1 Fringing Reef,1, 1 Fringing Reef Coral Transect Pole 1-2
Quadrat 1,t,Acanthastrea,0,HP+MEM
2005,2005-04-30, 1 Fringing Reef,1, 1 Fringing Reef
2005 Jan 03
0
LME-glmmPQL formulation
Hi all -
R2.0.1 on OSX;MASS library;nlme library
I am trying to emulate the solution to a problem set that has normally
been run in Genstat, using R. The problem that I am having at the
moment is with the following glmm question (using glmmPQL from the MASS
library):
"We have two different forest habitats (first rotation thicket, and
high forest) which we want to survey for the
2003 Feb 12
1
Na/NaN error in subsampling script
R-help readers,
I''m having a problem with an R script (see below), which regularly generates the error message,
Error in start:(start + (sample.length - 1)) :
NA/NaN argument
, for which I am unsure of the cause.
In essence, the script (below) generates the start and end points for random subsamples from along a vector (in reality a transect (of a given length,
2010 Aug 13
1
loop for inserting rows in a matrix
Dear R friends,
I have a matrix with 2060 rows and 41 columns. One column is Date, another is Transect, and another is Segment. I want to ensure that there are 9 Transects (1 to 9) for each Date, and 8 Segments (1 to 8) for each Transect in the matrix, by inserting rows where these are missing.
I am new to coding, but am trying to write a loop which checks if each of the transects already
2006 Feb 26
2
subtotal, submean, aggregate
Dear All,
I would like to make partial sums (or means or any other function) of
the values in intervals along a sequence (spatial transect) where groups
are defined.
For instance:
habitats<-rep(c("meadow","forest","meadow","pasture"),c(10,5,12,6))
observations<-rpois(length(habitats),2)
2011 Nov 18
1
One-way repeated measures ANOVA
Hi all,
I'm trying to run a repeated measures ANOVA on some univariate ecological
data that was collected over two growing seasons. I ran the test using the
methodology found on this website:
http://rtutorialseries.blogspot.com/2011/02/r-tutorial-series-one-way-repeated.html
Upon running the actual ANOVA I got this error message:
"> rmanova=anova(yearmodel, idata=yearframe,
2013 Jun 07
0
error running mvabund package
Dear All,
This is my first post, and probably (and hence apologies that) my question
is very silly!
I'm having issues with a the mvabund package
(http://cran.r-project.org/web/packages/mvabund/index.html),
and would be great to get some help!
Here is the code (and files are attached):
library(mvabund)
##visualizing data
florabund <- read.csv("CPL_floristics_abund_v1d.csv",
2008 Aug 17
1
before-after control-impact analysis with R
Hello everybody,
In am trying to analyse a BACI experiment and I really want to do it
with R (which I find really exciting). So, before moving on I though it
would be a good idea to repeat some known experiments which are quite
similar to my own. I tried to reproduce 2 published examples but without
much success. The first one in particular is a published dataset
analysed with SAS by
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 Aug 20
0
Re: Re: Your application
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2003 Aug 20
0
Re: Re: That movie
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2003 Aug 20
0
Re: Re: Wicked screensaver
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2011 Sep 08
1
random sampling but with caveats!
Hi,
I wonder if someone can help me. I have built a gam model to predict the presence of cold water corals and am now trying to evaluate my model by splitting my dataset into training/test datasets.
In an ideal world I would use the sample() function to randomly select rows of data for me so for example with 936 rows of data in my HH dataset I might say
ss <- sample(nrow(HH), size =
2011 Oct 09
3
ANOVA from imported data has only 1 degree of freedom
Hi,
I'm trying to analyse some data I have imported into R from a .csv file but
when I carry out the aov command the results show only one degree of freedom
when there should be 14. Does anyone know why? I'd really appreciate some
help, the data is pasted below.
/The imported table looks ike this this:/
Order Transect Sample Abundance
1 Coleoptera 1 1 13
2
2005 May 19
0
Random/systematic selection of rows in a matrix
Hi R people:
I am new to R. I am writing a function to (1) produce a sparse
stochastic Gaussian 2D field and (2) perform a systematic
transect sampling on this field, this carried out many times
in a simulation framework. My function does a good job at
producing the random field (a matrix of zeros and some
manifestations of the stochastic process, depending on a
parameter of the function