Displaying 19 results from an estimated 19 matches similar to: "Poisson GLM"
2006 Jan 29
1
extracting 'Z' value from a glm result
Hello R users
I like to extract z values for x1 and x2. I know how to extract coefficents
using model$coef
but I don't know how to extract z values for each of independent variable. I
looked around
using names(model) but I couldn't find how to extract z values.
Any help would be appreciated.
Thanks
TM
#########################################################
>summary(model)
Call:
2009 Aug 19
3
Sweave output from print.summary.glm is too wide
Hi all
I am preparing a document using Sweave; a really useful tool. But I am having a problem.
Consider this toy example Sweave file:
\documentclass{article}
\begin{document}
<<echo=TRUE,results=verbatim>>=
options(width=40) # Set width to 40 characters
hide <- capture.output(example(glm)) # Create an example of the problem, but hide the output
summary(glm.D93) #
2000 May 09
4
Dispersion in summary.glm() with binomial & poisson link
Following p.206 of "Statistical Models in S", I wish to change
the code for summary.glm() so that it estimates the dispersion
for binomial & poisson models when the parameter dispersion is
set to zero. The following changes [insertion of ||dispersion==0
at one point; and !is.null(dispersion) at another] will do the trick:
"summary.glm" <-
function(object, dispersion =
2009 Jun 05
2
p-values from VGAM function vglm
Anyone know how to get p-values for the t-values from the coefficients
produced in vglm?
Attached is the code and output ? see comment added to output to show
where I need p-values
+ print(paste("********** Using VGAM function gamma2 **********"))
+ modl2<-
vglm(MidPoint~Count,gamma2,data=modl.subset,trace=TRUE,crit="c")
+ print(coef(modl2,matrix=TRUE))
2009 Feb 16
1
Overdispersion with binomial distribution
I am attempting to run a glm with a binomial model to analyze proportion
data.
I have been following Crawley's book closely and am wondering if there is
an accepted standard for how much is too much overdispersion? (e.g. change
in AIC has an accepted standard of 2).
In the example, he fits several models, binomial and quasibinomial and then
accepts the quasibinomial.
The output for residual
2009 Dec 03
2
Avoiding singular fits in rlm
I keep coming back to this problem of singular fits in rlm (MASS library),
but cannot figure out a good solution.
I am fitting a linear model with a factor variable, like
lm( Y ~ factorVar)
and this works fine. lm knows to construct the contrast matrix the way I
would expect, which puts the first factor as the baseline level.
But when I try
rlm( Y ~ factorVar)
I get the message "'x'
2003 Jan 16
3
Overdispersed poisson - negative observation
Dear R users
I have been looking for functions that can deal with overdispersed poisson
models. Some (one) of the observations are negative. According to actuarial
literature (England & Verall, Stochastic Claims Reserving in General
Insurance , Institute of Actiuaries 2002) this can be handled through the
use of quasi likelihoods instead of normal likelihoods. The presence of
negatives is not
2008 Jan 05
2
Behavior of ordered factors in glm
I have a variable which is roughly age categories in decades. In the
original data, it came in coded:
> str(xxx)
'data.frame': 58271 obs. of 29 variables:
$ issuecat : Factor w/ 5 levels "0 - 39","40 - 49",..: 1 1 1 1...
snip
I then defined issuecat as ordered:
> xxx$issuecat<-as.ordered(xxx$issuecat)
When I include issuecat in a glm model, the result
2011 Feb 08
1
Error in example Glm rms package
Hi all!
I've got this error while running
example(Glm)
library("rms")
> example(Glm)
Glm> ## Dobson (1990) Page 93: Randomized Controlled Trial :
Glm> counts <- c(18,17,15,20,10,20,25,13,12)
Glm> outcome <- gl(3,1,9)
Glm> treatment <- gl(3,3)
Glm> f <- glm(counts ~ outcome + treatment, family=poisson())
Glm> f
Call: glm(formula = counts ~
2006 Oct 10
0
Haplo.Stats: error (recursive default argument reference)
Dear colleagues,
I face a problem doing haplotype analyses with haplostats: when I use
the haplo.em function, the programme gives an error message because of
'recursive default argument reference.' I am not able to figure out what
this means. Could you perhaps help me?
The full output is the following:
> library(haplo.stats)
>
2009 May 18
2
Overdispersion using repeated measures lmer
Dear All
I am trying to do a repeated measures analysis using lmer and have a number
of issues. I have non-orthogonal, unbalanced data. Count data was obtained
over 10 months for three treatments, which were arranged into 6 blocks.
Treatment is not nested in Block but crossed, as I originally designed an
orthogonal, balanced experiment but subsequently lost a treatment from 2
blocks. My
2009 Nov 07
1
lme4 and incomplete block design
Dear list members,
I try to simulate an incomplete block design in which every participants
receives 3 out of 4 possible treatment. The outcome in binary.
Assigning a binary outcome to the BIB or PBIB dataset of the package
SASmixed gives the appropriate output.
With the code below, fixed treatment estimates are not given for each of
the 4 possible treatments, instead a kind of summary
2005 Sep 07
1
FW: Re: Doubt about nested aov output
Ronaldo,
Further to my previous posting on your Glycogen nested aov model.
Having read Douglas Bates' response and Reflected on his lmer analysis
output of your aov nested model example as given.The Glycogen treatment has
to be a Fixed Effect.If a 'treatment' isn't a Fixed Effect what is ? If
Douglas Bates' lmer model is modified to treat Glycogen Treatment as a
purely
2008 Oct 09
1
Interpretation in cor()
Hello,
I am performing cor() of some of my data. For example, I'll do 3 corr()
(many variables) operations, one for each of the three treatments.
I then do the following:
i <-lower.tri(treatment1.cor)
cor(cbind(one = treatment1.corr[i], two = treatment2.corr[i], three =
treatment3.corr[i]))
Does this operation above tell me how correlated each of the three
treatments is? Because this
2011 Nov 24
0
loop through columns in S4 objects
Dear experts,
I am trying to perform an association using snpStats.
I have a snp matrix called 'plink' which contains my genotype data (as
a list of $genotypes, $map, $fam), and a phenotype data frame which
contains the outcomes (outcome1, outcome2,...) I would like to
associate with the genotype.
My question is, how do I loop through the outcomes? This type of data
seems different from
2006 May 09
2
post hoc comparison in repeated measure
Hi, I have a simple dataset with repeated measures.
one factor is treatment with 3 levels (treatment1,
treatment2 and control), the other factor is time (15
time points). Each treatment group has 10 subjects
with each followed up at each time points, the
response variable is numeric, serum protein amount. So
the between subject factor is treatment, and the
within subject factor is time. I ran a
2008 Sep 17
1
ANOVA contrast matrix vs. TukeyHSD?
Dear Help List,
Thanks in advance for reading...I hope my questions are not too ignorant.
I have an experiment looking at evolution of wing size [centroid] in
fruitflies and the effect of 6 different experimental treatments
[treatment]. I have five replicate populations [replic] in each
treatment and have reared the flies in two different temperatures [cond]
to assay the wing size, making
2010 Aug 18
1
reading lmer table
Dear all,
I'm quite new in R and especially with linear mixed effects models and
I'm not completely sure to read the lmer table in the right way.
for example:
head(march.f)
fam subjID Cond Code reg total first
second log.total log.second cat
3 f 30 an fDan1 3 1.2304688 0.6679688 0.56250000
0.20739519 0.44628710 f
2009 Feb 24
2
Simulating contingency table (Basic question, help please)
I'd like to carry out a Monte Carlo simulation test where given data is a
contingency table. I think this is something to do with using rmultinonom(),
but I'm not sure how to code this, to simulate contingency tables. Could
anyone please help with how to use R to simulate contingency tables like
this?
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