Displaying 20 results from an estimated 2000 matches similar to: "Discrepancy of Neg. Binomial Estimation in R"
2011 Jun 27
1
Neg Binomial In GEE
Hi, I want to fit a GEE with a negative binomial distribution. I have uesd
already a poisson glm and then neg binommial to deal with alot of
dispersion. In my neg binomial residuals i have some patterns so i have
implemented a GEE, but only with a poisson family as i couldnt with neg
binomial. However the residual patterns in fact look worse here. When i
try and put neg binomial family it
2011 Oct 13
2
GLM and Neg. Binomial models
Hi userRs!
I am trying to fit some GLM-poisson and neg.binomial. The neg. Binomial
model is to account for over-dispersion.
When I fit the poisson model i get:
(Dispersion parameter for poisson family taken to be 1)
However, if I estimate the dispersion coefficient by means of:
sum(residuals(fit,type="pearson")^2)/fit$df.res
I obtained 2.4. This is theory means over-dispersion since
2014 Nov 23
3
[Bug 86618] New: [NV96] neg modifiers not working in MIN and MAX operations
https://bugs.freedesktop.org/show_bug.cgi?id=86618
Bug ID: 86618
Summary: [NV96] neg modifiers not working in MIN and MAX
operations
Product: Mesa
Version: git
Hardware: Other
OS: All
Status: NEW
Severity: normal
Priority: medium
Component: Drivers/DRI/nouveau
2009 Feb 18
1
Help on warning message from Neg. Binomial error during glm
I am using glm.nb, a ~b*c ( b is categorical and c is continuous). when I
run this model I get the warning message:
Warning messages:
1: In theta.ml(Y, mu, sum(w), w, limit = control$maxit, trace =
control$trace > :
iteration limit reached
2: In theta.ml(Y, mu, sum(w), w, limit = control$maxit, trace =
control$trace > :
iteration limit reached
What does this mean?
--
Graduate
2009 Nov 26
0
R: RE: R: Re: R: Re: chol( neg.def.matrix ) WAS: Re: Choleski and Choleski with pivoting of matrix fails
Thanks for your message!
Actually it works quite well for me too.
If I then take the trace of the final result below, I end up with a number
made up of both a real and an imaginary part. This does not probably mean much
if the trace of the matrix below givens me info about the degrees of freedom of
a model...
Simona
>----Messaggio originale----
>Da: RVaradhan at jhmi.edu
>Data:
2010 Feb 08
0
Poisson and neg. bin. regression with random effects
Hi there,
I have relative abundance data for 13 mammal species that I collected at various sites that ranged in road density. I'm trying to determine the effect of road density on animal abundance across body sizes. For most species, I have data that was collected in one year but for a few species I have two years of complete data, and would like to use both. Since I have count data, I'm
2014 Nov 23
0
[PATCH] nv50/ir: set neg modifiers on min/max args
Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=86618
Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---
src/gallium/drivers/nouveau/codegen/nv50_ir_emit_nv50.cpp | 2 ++
1 file changed, 2 insertions(+)
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_nv50.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_nv50.cpp
index 077eba8..3048f3d 100644
---
2006 Sep 22
2
"logistic" + "neg binomial" + ...
Hi Folks,
I've just come across a kind of problem which leads
me to wonder how to approach it in R.
Basically, each a set of items is subjected to a series
of "impacts" until it eventually "fails". The "force"
of each impact would depend on covariates X,Y say;
but as a result of preceding impacts an item would be
expected to have a "cumulative
2009 Nov 23
1
R: Re: chol( neg.def.matrix ) WAS: Re: Choleski and Choleski with pivoting of matrix fails
It works! But Once I have the square root of this matrix, how do I convert it
to a real (not imaginary) matrix which has the same property? Is that
possible?
Best,
Simon
>----Messaggio originale----
>Da: p.dalgaard at biostat.ku.dk
>Data: 21-nov-2009 18.56
>A: "Charles C. Berry"<cberry at tajo.ucsd.edu>
>Cc: "simona.racioppi at
2009 Nov 25
1
R: Re: R: Re: chol( neg.def.matrix ) WAS: Re: Choleski and Choleski with pivoting of matrix fails
Dear Peter,
thank you very much for your answer.
My problem is that I need to calculate the following quantity:
solve(chol(A)%*%Y)
Y is a 3*3 diagonal matrix and A is a 3*3 matrix. Unfortunately one
eigenvalue of A is negative. I can anyway take the square root of A but when I
multiply it by Y, the imaginary part of the square root of A is dropped, and I
do not get the right answer.
I tried
2005 Jun 30
1
RE : Dispersion parameter in Neg Bin GLM
Edward, you also can use the package aod on CRAN, see the help page of the function negbin.
Best
Matthieu
An example:
> library(aod)
> data(dja)
> negbin(y ~ group + offset(log(trisk)), ~group, dja, fixpar = list(4, 0))
Negative-binomial model
-----------------------
negbin(formula = y ~ group + offset(log(trisk)), random = ~group,
data = dja, fixpar = list(4, 0))
2006 Nov 06
4
neg-bin clustered analysis in R?
Dear All,
I'm analysing a negative binomial dataset from a population-based
study. Many covariates were determined on household level, so all
members of a household have the same value for those covariates.
In STATA, there seems to be an option for 'clustered analysis' for
neg-bin regression. Does an equivalent exist for R(MASS)'s glm.nb or a
comparable function?
Many thanks for
2011 Sep 22
1
Error in as.vector(data) optim() / fkf()
Dear R users,
When running the program below I receive the following error message:
fit <- optim(parm, objective, yt = tyield, hessian = TRUE)
Error in as.vector(data) :
no method for coercing this S4 class to a vector
I can't figure out what the problem is exactly. I imagine that it has
something to do with "tyield" being a matrix. Any help on explaining what's
going on
2006 Jun 09
1
glm with negative binomial family
I am analysing parasite egg count data and am having trouble with glm with a
negative binomial family.
In my first data set, 55% of the 3000 cases have a zero count, and the
non-zero counts range from 94 to 145,781.
Eventually, I want to run bic.glm, so I need to be able to use glm(family=
neg.bin(theta)). But first I ran glm.nb to get an estimate of theta:
> hook.nb<- glm.nb(fh,
2009 Oct 29
1
lmer and negative binomial family
Dear listers,
One of my former students is trying to fit a model of the negative
binomial family with lmer. In the past (two years ago), the following
call was working well:
m1a<-lmer(mapos~ninter+saison+milieu*zone+(1|code),family=neg.bin(0.451),REML=TRUE,data=manu)
But now (R version 2.9.2 and lme4 version 0.999375-32), that gives
(even with the library MASS loaded):
2011 Nov 12
1
State space model
Hi,
I'm trying to estimate the parameters of a state space model of the
following form
measurement eq:
z_t = a + b*y_t + eps_t
transition eq
y_t+h = (I -exp(-hL))theta + exp(-hL)y_t+ eta_{t+h}.
The problem is that the distribution of the innovations of the transition
equation depend on the previous value of the state variable.
To be exact: y_t|y_{t-1} ~N(mu, Q_t) where Q is a diagonal
2006 Jun 05
1
negative binomial: expected number of events?
Hi
I'm fitting poisson and negative binomial distributions to event data. I'm
interested in the expected number of events occuring in a time period. For
the poisson this is determined by the parameter lambda only.
For the neg. binomial, is the expected number of events determined by the
parameter "mu" only or does parameter "size" influence the first moment as
2002 Oct 28
2
glmm for binomial data? (OT)
A while ago (April 2002) there was a short thread on software for generalized
linear mixed models.
Since that time, has anyone written or found R code to use a glmm to analyze
binomial data? I study CWD in white-tailed deer, and I'd like to do a
similar analysis as Kleinschmidt et al. (2001, Am. J. Epidemiology 153:
1213-1221) used to assess control for spatial structure in malaria
2006 Sep 01
0
defining error structure in bivariate mixed models
Hi,
Using indicator variables I have been able to fit and run the code for
fitting a bivariate mixed model using unstructured covariance matrix
The code is
lme.fit1<- lme(one.var~-1+indic1+indic2+I(indic1*d.time)+I(indic2*d.time),
random =~ -1+indic1+indic2|m.unit, weights = varIdent(~1|indic1)
,data = new.data)
My variables are
one.var :- the two response variables stacked one after
2004 Jun 07
2
MCLUST Covariance Parameterization.
Hello all (especially MCLUS users).
I'm trying to make use of the MCLUST package by C. Fraley and A. Raftery. My problem is trying to figure out how the (model) identifier (e.g, EII, VII, VVI, etc.) relates to the covariance matrix. The parameterization of the covariance matrix makes use of the method of decomposition in Banfield and Rraftery (1993) and Fraley and Raftery (2002) where