Displaying 20 results from an estimated 500 matches similar to: "How to interpret vglm output!!"
2011 Oct 12
1
Generelized Negative Binomial model in R
Hello;
Does anybody knows that R have a function for Generelized Negative Binomial
model, something like "gnbreg" in "STATA" where dispersion parameter itself
is a function of covaraites ?
Thanks;
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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))
2007 Oct 29
1
VGAM and vglm
Hi Folks,
I wonderif someone who is familiar with the details
of vglm in the VGAM package can assist me. I'm new
to using it, and there doesn;t seem much in the
documentation that's relevant to the question below.
Say I have a vector x of 0/1 responses and another
vector y of 0/1 responses, these in fact being a
bivariate set of 0/1 responses equivalent to
cbind(x,y).
E.g.
2011 Jan 23
1
extract score vector and covariance matrix in glm package
Hello
I am running a project but I encounter a problem . I would be happy
to receive help :
problem:
I have a binary dependent variable and some covariates logit(y)=a+bx+cz .
I want to estimate the score vectors and their covariance by the usage of
logit function and so glm in R .The vlaue of one of the coefficient (
like b) is known previously and I want to extract a and c and covariance
2011 Oct 11
1
Count model prediction
Hello ;
I am doing a regression of count data (number of award and there are some
covariates)
I have estiamted the parameters of negative binomial distribuion (lambda is
a function of covaraites, GLM model) by glm.nb function and training
dataset.
Now I want to predict the number of award (for example y=0, y=1, y=2,) or
testing dataset. I dont know how to calculate this numbers?
I would be very
2008 Jan 07
0
R vglm new family writing: mix Poisson/multinomial
Hi dear R users,
1)
I would like to know if there is a simple way to define a vglm family which
would be a mix of poisson variables and bernoulli variables (0/1 response)
for idea this would be invoked like this:
vglm(...,family=mixpoissonmultinom(npoisson,n01response))
where the n's give the number of each type of response.
2)
and a simpler question : How to use constraints in rrvglm?
2009 Nov 04
1
vglm(), t values and p values
Hi All,
I'm fitting an proportional odds model using vglm() from VGAM.
My response variable is the severity of diseases, going from 0 to 5 (the
severity is actually an ordered factor).
The independent variables are: 1 genetic marker, time of medical observation,
age, sex. What I *need* is a p-value for the genetic marker. Because I have ~1.5
million markers I'd rather not faffing
2011 Aug 23
1
P values for vglm(zibinomial) function in VGAM
Hi ,
I know this question has been asked twice in the past but to my knowldege,
it still hasn't been solved.
I am doing a zero inflated binomial model using the VGAM package, I need to
obtain p values for my Tvalues in the vglm output. code is as follows
> mod2=vglm(dmat~Season+Diel+Tidal.phase+Tidal.cycle,zibinomial, data=mp1)
> summary(mod2)
Call:
vglm(formula = dmat ~ Season +
2012 Mar 21
0
multivariate ordinal probit regression vglm()
Hello, all.
I'm investigating the rate at which skeletal joint surfaces pass
through a series of ordered stages (changes in morphology). Current
statistical methods in this type of research use various logit or
probit regression techniques (e.g., proportional odds logit/probit,
forward/backward continuation ratio, or restricted/unrestricted
cumulative probit). Data typically include the
2011 Aug 17
0
vglm regression with weibull distribution
Dear all,
I'm facing a problem in estimation of glm model with weibull distribution. I run this :
eqn0<-formula(fdh~cup1+cup2+cup3+cup4+fin1+vd1+cm2+cm4+milieu+cpro1+cpro2+cpro3a+cpro3b+schef+log(y))
regWeib0<-vglm(eqn0,family=weibull,subset(br, fdh<1))
I have en estimation but there is a message saying that regularity conditions are violated :
Message d'avis :
In eval(expr,
2007 Jan 06
2
Using VGAM's vglm function for ordinal logistic regression
R-Experts:
I am using the vglm function of the VGAM library to perform proportional
odds ordinal logistic regression. The issue that I would like help with
concerns the format in which the response variable must be provided for
this function to work correctly. Consider the following example:
------
library(VGAM)
library(MASS)
attach(pneumo)
pneumo # Inspect the format of the original dataset
2007 Jul 16
2
Error while fitting Partial Proportional Odds model using vglm
Dear R developers:
I am trying to fit a PPO model using vglm from the library VGAM, and get an
error while executing the code. Here is the data, code, and error:
Data: first row is the column names. a = age, and 1,2,3, 4 and 5 are
condition grades.
a 1 2 3 4 5
1 1 0 0 0 0
2 84 2 7 10 2
3 16 0 6 6 2
4 13 0 3 4 0
5 0 0 0 1 0
Library(VGAM)
2007 Nov 16
1
constraint matrices in vglm (VGAM package)
Hello R users,
I am performing a multinomial logit regression and would like to
constrain a few model coefficients to be equal.
Here is my model:
multi <- vglm(case123con ~ SNP_A1+SNP_A2+age, multinomial, work.analy)
where case123con is a four level categorical variable (case 1, case 2,
case 3, control) and SNP_A1 and SNP_A2 are indicator functions (yes/no).
The output of this
2011 Jul 06
0
Leverage values in VGLM
Hi,
I just want to know how to get leverage values in VGLM(Adjacent category
logit model, *acat()*) model
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2008 Dec 08
0
multinomial losgitic regression--vglm()
Dear:
I try to analysis multinomial logistic regression using vglm in VGAM package. However, I wonder how many levels of responses variable this command is suitable. I saw the examples in google search works for 3 levels, say 1,2,3. However, my response variable is more than 3 levels. Is it working for my case or have alternative approach?
Many thanks!
Xin
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2012 Jun 05
0
Improper coding for an offset in vglm()?
Hello R-help.
I believe I may be coding the offset incorrectly in my formula. I am
testing significance between different group pairings using the VGAM
package. My data are zero-truncated and poisson-distributed and
overdispersed, so I'm using the posnegbinomial function in vglm (code
below). I've spent a very long time working out this model and am pretty
sure it's the best for
2010 Aug 31
4
vglm
Hi All,
could anybody help me to understand what is this error means ?
mydata=read.table("C:/Documents and
Settings/angieb/Desktop/CommercialGL/cl_ilf_claimdata.csv",header=TRUE,sep=",")
> names(mydata)
[1] "ILFTable" "liabLimit" "AnnAggLimit" "DedAmt" "Loss"
"TIL"
>
2011 Sep 05
2
Need more information about VGLM
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2013 Apr 17
1
Bug in VGAM z value and coefficient ?
Dear,
When i multiply the y of a regression by 10, I would expect that the
coefficient would be multiply by 10 and the z value to stay constant. Here
some reproducible code to support the case.
*Ex 1*
library(mvtnorm)
library(VGAM)
set.seed(1)
x=rmvnorm(1000,sigma=matrix(c(1,0.75,0.75,1),2,2))
2009 Jun 16
0
Generation from COX PH with gamma frailty
Hello,
I want to generate data set from Cox PH model with gamma frailty effects.
theta(parameter for frailty distribution)=2
beta=1.5
n=300
cluster size=30
number of clusters=10
I think I should first generate u from Gamma(Theta,theta) and then using
this theta I could not decide how I should generate the survival times?
Is there any package for this? or any document you could suggest?
Any