Displaying 20 results from an estimated 200 matches similar to: "Problem in lme longitudinal model"
2011 Mar 25
1
spatial stats - geoR - variogram - standard deviation
Hello,
I am attempting to get the standard deviation in multiple distance bins in
my spatial data.
It appears as though the 'variog' command in the geoR package will do the
trick, as one of the outputs from 'variog' is 'variog$sd', which,
according to the manual, is the "standard deviation of the values in each
bin".
However, when I run this command, the
2006 Jun 02
1
geoR, plot of variog4 lines incomplete
I'm using R for Mac OSX version 1.14 (2129) and the geoR package
version 1.6-5 (the current version in the R repository). I'm running
R in OS 10.4.6 on a Mac G4 iBook (933MHz, 640 MB DDR SDRAM). I
searched the R archive and did not find a posting on this issue.
I want to use the variog and variog4 functions of geoR to
characterize the pattern of spatial autocorrelation of tree
2004 Nov 18
0
implementing a "loop" using by(x,x$factor,FUN)
Hi,
I'm writing some R code that requires a massive amount of looping and would
ideally like to write it so that it avoid the use of "for" loop ... however I'm
having some trouble.
Very briefly, the basic idea is to implement a binary partitioning algorithm to
determine the optimal cutpoint based on deviance measures obtained from
likelihood estiamtes. This is in the
2008 Jul 25
0
Error in vector("double", length)
Please see the code below.
When I try to run the variogram - vg.deft<-variog(rd,uvec=10)
I keep getting this error-
variog: computing omnidirectional variogram
Error in vector("double", length) : vector size specified is too large
Also, when I try to define distance-based neighborhood -
nb.tr=dist.neighbors(tr.locs,2)
I get this error -
Error in vector("double", length) :
2003 Feb 11
2
geoR question from new R user
Hi,
I'm a new R user. My goal is to do a variogram using geoR.
I started by trying to do the example in the geoR Illustrative Session
using my own data.
I am able to read in my Ascii data using: D <- matrix(scan("file.dat",
n=530*3), 530,3, byrow=TRUE).
Then I use: as.geodata(D, coords.col=1:2, data.col=3) to make the
object D geodata.
I check the descriptive statistics,
2003 Sep 10
1
geoR variogram problem
Dear GeoR-er,
If I use the variog function in the latest release of geoR, the first lag is
always ignored.
For instance, if you read in geodata, calculates the variogram using the
variog function and give in a uvec like uvec=seq(0,max,by=2.44), it only
starts giving results from distance=4.88 and ignores 2.44!
This wasn't the case in former versions of geoR. Is this done on purpose?
Why?
2009 Sep 17
0
geoR, variofit
Hello All!
I calculate a variogram using the function variog (package geoR)
afterwards I use variofit to fit a spherical model (see code below).
Now I just changed the units of the variable (in this case MPa to kPa
just a factor of 1000). If I do so, I get a different fit and
therefore different ranges etc. Why? The semi-variance is of course 6
orders of magnitude higher but the values
2008 Aug 15
1
Strange error message from geoR´s likfit () lik. max. func.
ComRades:
I am geeting the error message
Error in ldots[[which(MET)]] : attempt to select less than one element
when I try to fit the geostatistical model with the likfit() function of
geoR.
I have tried with old data for which likfit() successfully maximised the
likelihood in previous versions of geoR, and yet the current version
fails.
I have tried in Windows Vista and Windows XP (I haven't
2011 Apr 12
1
How to set the dimension of a matrix correctly?
Hi all,
I use kriging to interpolate the precipitation from stations, but the map of this results show lots of stripes. (please see the attachment)I think there's something wrong with the setting of the dimension of this matrix, however, I have no idea how to know or test to see if this setting is correct or not.I've tried to switch the latitude and longitude, but still got the same
2006 Jun 03
1
default value for cutoff in gstat variogram()
I wonder what is the default value for the argument 'cutoff' when not
specified in the variogram.formula function of gstat. Computing
variogram envelops within gstat, I am comparing the results obtained
with variog in geoR and variogram in gstat, and it took me a while
before understanding that the cutoff default value is not the maximum
distance.
Can Edzer tell us about it?
All the
2007 Oct 28
1
gam for longitudinal data?
I used gam for data analysis a lot. Is it possible to use gam to analyze
longitudinal data? I mean, besides the working independence assumption, can
i specify other more reasonable covariance structure in gam?
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2008 Dec 05
0
Quantile Regression for longitudinal data
Hi all,
does anybody know about R implementations for quantile regression for
longitudinal data? I am just aware of a very basic version of R.
Koenker's approach using fixed effects.
Thanks in advance
Armin
2009 May 06
0
Quantile Regression for Longitudinal Data. Warning message: In rq.fit.sfn
Dear Dimitris, I have exactly the same problem
than you, Do you get some solution?
Thanks, Lola
Lola Gadea
Profesora titular de Economía Aplicada/Lecturer in Applied Economics
Universidad de Zaragoza/University of Zaragoza (Spain)
lgadea@unizar.es
<http://estructuraehistoria.unizar.es/personal/lgadea/index.html>http://estructuraehistoria.unizar.es/personal/lgadea/index.html
Grupo de
2012 Oct 21
0
longitudinal data
I would like to use GLM to analysis a longitudinal data
any one know which library in R do so
thanks alot
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2009 Jul 17
1
package to do inverse probability weighting in longitudinal data
Hi there,
I have a dataset from a longitudinal study with a lot of drop-out. I
want to implement the inverse probability weighting method by Robins
1995 JASA paper "Analysis of semiparametric regression models for
repeated outcomes in the presence of missing data". Does anyone know
if there is a package to do it in R (or other software)? Thanks a lot!
Lei
2010 Jun 30
0
longitudinal tobit regression in R
Hi,
I am trying to model a score over time. This score shows a ceiling effect. I was
willing to use a longitudinal tobit model, such as the one described by Twisk et
al. (Twisk_Longitudinal tobit regression: A new approach to analyze outcome
variables with floor or ceiling effects_JCE_2009) but it is programmed for
STATA.
Has anyone used such models in R?
Any other idea?
David Biau.
2007 May 11
0
Multivariate longitudinal sample data
Hi,
Can anyone recommend one or more good sample datasets for multivariate
longitudinal data? (eg. a dataset containing a mixture of continuous,
categorical and date/time variables) I'm looking for something which
I can use for testing and examples for my ggplot graphics package. A
selection of datasets which use different date time classes would also
be useful, although I could probably
2009 Jul 15
0
strategy to iterate over repeated measures/longitudinal data
Hi Group,
Create some example data.
set.seed(1)
wide_data <- data.frame(
id=c(1:10),
predictor1 = sample(c("a","b"),10,replace=TRUE),
predictor2 = sample(c("a","b"),10,replace=TRUE),
predictor3 = sample(c("a","b"),10,replace=TRUE),
measurement1=rnorm(10),
measurement2=rnorm(10))
head(wide_data)
id
2007 Sep 24
0
longitudinal imputation with PAN
Hello all,
I am working on a longitudinal study of children in the UK and trying the PAN package for imputation of missing data, since it fulfils the critical criteria of taking into account individual subject trend over time as well as population trend over time. In order to validate the procedure I have started by deleting some known values ?we have 6 annual measures of height on 300 children
2001 Jul 04
0
Regression trees with longitudinal data
Hi,
Can anyone tell me if they know of any functions written for
regression trees with a longitudinal dataset. I've got tree, rpart and
maptree, but these all seem to be for univariate responses.
Thanks for your time,
Cath
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