Displaying 20 results from an estimated 500 matches similar to: "IWLS vs direct ML estimation"
2009 Jul 29
3
how to skip a numeric column for averaging other columns?
Data has the first row for variable name and the first column for sample
name. I want to take "Log" for all data, but how to compute without the
first column for sample name.
That is,
column 1: sample ID
column 2-10: data
I want to find an average on each column (2-10)
> apply(raw_data,2,mean)
Error in Math.data.frame(list(sample_id = c(1L, 2L, 3L, 4L, 5L, 6L, 7L, :
2008 Sep 29
3
count data with a specific range
Hi there,
The data is
data<-c(2,6,13,26,19,25,18,11,22,25)
I want to count data for these rages:
[0~10]:
[11~20]:
[21-30]:
Is anyone can help me?
Thank you in advance
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2008 Nov 01
2
calculation for standard normal cumulative distribution
Is there anyone knowing a function or way for standard normal cumulative
distribution?
?(z=-0.1)=?
also
?(z=?)=0.025
Thank you,
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2012 Nov 06
1
glm fitting routine and convergence
What kind of special magic does glm have?
I'm working on a logistic regression solver (L-BFGS) in c and I've been
using glm to check my results. I came across a data set that has a very
high condition number (the data matrix transpose the data matrix) that when
running my solver does not converge, but the same data set with glm was
converging ( I love R :) ). I noticed that glm using
2008 Jul 23
3
maximum likelihood method to fit a model
Dear R users,
I use the glm() function to fit a generalized linear model with gamma distribution function and log link.
I have read in the help page that the default method used by R is "glm.fit" (iteratively reweighted least squares, IWLS).
Is it possible to use maximum likelihood method?
Thanks
Silvia Narduzzi
Dipartimento di Epidemiologia
ASL RM E
Via di S. Costanza, 53
00198
2004 Nov 19
2
glm with Newton Raphson
Hi,
Does anyone know if there is a function to find the maximum likelihood
estimates of glm using Newton Raphson metodology instead of using IWLS.
Thanks
Valeska Andreozzi
--------------------------------------------------------
Department of Epidemiology and Quantitative Methods
FIOCRUZ - National School of Public Health
Tel: (55) 21 2598 2872
Rio de Janeiro - Brazil
2006 Jan 12
1
Firths bias correction for log-linear models
Dear R-Help List,
I'm trying to implement Firth's (1993) bias correction for log-linear models.
Firth (1993) states that such a correction can be implemented by supplementing
the data with a function of h_i, the diagonals from the hat matrix, but doesn't
provide further details. I can see that for a saturated log-linear model, h_i=1
for all i, hence one just adds 1/2 to each count,
2008 Mar 18
1
glm poisson, method='ML' (PR#10985)
Full_Name: saraux
Version: 2.6.1
OS: Windows vista
Submission from: (NULL) (193.157.180.37)
I would like to compute a glm with a distribution of poisson, using a maximum of
likelihood method. But it seems not to work with a distribution of poisson. The
same code with another distrubution (binomial for example) works.
Here is the command I typed:
2001 Oct 10
2
Pearson residuals (PR#1123)
Full_Name: Carmen Fernandez
Version: 1.3.1
OS:
Submission from: (NULL) (138.251.202.115)
I think there is a problem when computing Pearson residuals, in that they seem
to be computed at the raw residuals divided by the square root of the
corresponding diagonal element of the weight matrix W evaluated at the last step
of the iterative model fitting procedure (IWLS), instead of dividing by the
2004 Jul 05
2
Failing on reading a "slightly big" dataset
I have a file with 4 columns per line, all pipe delimited.
$ wc -l cmie_firm_data.text
89325 cmie_firm_data.text
$ ls -al cmie_firm_data.text
-rw-r--r-- 1 ajayshah ajayshah 4415637 Jul 5 15:25 cmie_firm_data.text
$ awk -F\| '(NF != 4)' cmie_firm_data.text
$ head cmie_firm_data.text
All figures are for the year 20030331|||
Company|GVA Less Interest (Rs. thousand)|Interest (Rs.
2008 Sep 19
2
Error: function cannot be evaluated at initial parameters
I have an error for a simple optimization problem. Is there anyone knowing
about this error?
lambda1=-9
lambda2=-6
L<-function(a){
s2i2f<-(exp(-lambda1*(250^a)-lambda2*(275^a-250^a))
-exp(-lambda1*(250^a)-lambda2*(300^a-250^a)))
logl<-log(s2i2f)
return(-logl)}
optim(1,L)
Error in optim(1, L) : function cannot be evaluated at initial parameters
Thank you in advance
--
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2007 Mar 30
1
Model comparison
Dear all,
I would like to know if I can compare by a significance test 2 models with different kind of parameters. Perhaps I am wrong but I think that we can only compare 2 models if one is a sub model of the other.
Med venlig hilsen / Regards
João Fadista
Ph.d. studerende / Ph.d. student
AARHUS UNIVERSITET / UNIVERSITY OF AARHUS
Det Jordbrugsvidenskabelige Fakultet / Faculty of
2009 Nov 23
1
Re moving rows which do not satisfy a condition
Hello,
Considering 5 points in X-Y plain. Data is a 5*2 matrix (5 rows for samples
& 2 columns for X and Y)
With a distance from the origin, if a distance < 7, remove the row from the
Data.
After calculating the distance for each point, I can't forward because of
this "Removing" problem.
Anyone can help me?
Data=matrix(1:10,5,2)
a=rep(0,5);
b=rep(0,5);
for (i in
2008 Sep 09
1
Genmod in SAS vs. glm in R
Hello,
I have different results from these two softwares for a simple binomial GLM
problem.
>From Genmod in SAS: LogLikelihood=-4.75, coeff(intercept)=-3.59,
coeff(x)=0.95
>From glm in R: LogLikelihood=-0.94, coeff(intercept)=-3.99, coeff(x)=1.36
Is there anyone tell me what I did wrong?
Here are the code and results,
1) SAS Genmod:
% r: # of failure
% k: size of a risk set
data
2012 Mar 07
4
Subset problem
Good Morning
??? I have a small question regarding the function subset.
I am copying data from one table but I just want to collect data from a
user.
When do I take the view, presents the results I want.
The problem arises when can I make the tab. for RES_ID, introduces me to
zero results do not envision noVIEW
val_user='16'
x.sub <-
2008 Sep 12
1
Error in "[<-"(`*tmp*`, i, value = numeric(0)) :
I use "while" loop but it produces an errro. I have no idea about this.
Error in "[<-"(`*tmp*`, i, value = numeric(0)) :
nothing to replace with
The problem description is
The likelihood includes two parameters to be estimated: lambda
(=beta0+beta1*x) and alpha. The algorithm for the estimation is as
following:
1) with alpha=0, estimate lambda (estimate beta0
1999 Feb 02
0
Re: glm and data.frames (PR#108)
jlindsey at alpha.luc.ac.be writes:
> The following is a bug or feature in recent versions. Try the
> following with a clean workspace:
>
> y <- cbind(rpois(20,4),rpois(20,4))
> df <- data.frame(y=y,x=rnorm(20))
> colnames(df)
> colnames(model.frame(y~x,data=df))
>
> Now start over with a clean workspace and try
>
> df <-
2004 May 17
1
residuals in multinom
Hi,
is there a possibility to calculate the different "types" of residuals
directly using the multinom function from MASS as it is possible for the
functions gam, glm
using type="deviance" or "working" or "pearson" or "response"? I tried it
but got always the "response" type, I guess.
thanx
Matthias
2011 Jan 02
3
changing method of estimation in GLM
can anyone tell me how can i control the method of estimation (i.e. scoring
method or Newton raphson method) in glm and compute deviance function ?
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1999 Apr 19
1
Algorithm used by glm, family=binomial?
Does anyone know what algorithm R uses in glm, family=binomial (i.e. a
logit model)?
I assume that it's in the source somewhere, but I wasn't able to find
it. I'd like to know
what file it's in (in a unix distribution of R).
Thanks for your help.
---------------------------
Barnet Wagman
wagman at enteract.com
1361 N. Hoyne, 2nd floor
Chicago, IL 60622
773-645-8369