Displaying 20 results from an estimated 700 matches similar to: "R"
2006 Jan 23
1
weighted likelihood for lme
Dear R users,
I'm trying to fit a simple random intercept model with a fixed intercept.
Suppose I want to assign a weight w_i to the i-th contribute to the log-likelihood, i.e.
w_i * logLik_i
where logLik_i is the log-likelihood for the i-th subject.
I want to maximize the likelihood for N subjects
Sum_i {w_i * logLik_i}
Here is a simple example to reproduce
2017 Aug 10
1
"Help On optim"
Hello,
I have some parameters from Mclust function. The parameters are in the form
*parametersDf *
* mu_1 mu_2 var_mc1 var_mc2 c1
c2 *
*2 1.357283 2.962736 0.466154 0.1320129 0.5258975
0.4741025 *
*21 8.357283 9.962736 0.466154 0.1320129 0.5258975
0.4741025 *
Each row in the above data frame
2008 Dec 18
1
svyglm fit method?
Dear list,
I am using svyglm in the survey library to fit a binomial logistic
regression accounting for sample design. The documentation says the
models are not fit by maximum likelihood, so my question is what is
the fitting method? Pseudo likelihood? Generalized least squares?
Thanks for any insight.
Best,
Corey
Corey Sparks
Assistant Professor
Department of Demography and
2005 Feb 15
1
shrinkage estimates in lme
Hello. Slope estimates in lme are shrinkage estimates which pull the
OLS slope estimates towards the population estimates, the degree of
which depends on the group sample size and the distance between the
group-based estimate and the overall population estimate. Although
these shrinkage estimates as said to be more precise with respect to the
true values, they are also biased. So there is a
2011 Dec 13
1
Should I use nls for this?
Hi,
I have a dataset with the following properties:
Y_i ~ N(mu_i, theta * (mu_i)^2)
ln(mu_i) = B'Xi
theta and beta's are the parameters here.
I want to come up with a model to fit the data with the above property and
test that model on the built in R dataset quine.
Does nls() make sense in this case? Or is there any existing R package which
can fit this model?
-Shelly
--
View
2007 Feb 01
3
Help with efficient double sum of max (X_i, Y_i) (X & Y vectors)
Greetings.
For R gurus this may be a no brainer, but I could not find pointers to
efficient computation of this beast in past help files.
Background - I wish to implement a Cramer-von Mises type test statistic
which involves double sums of max(X_i,Y_j) where X and Y are vectors of
differing length.
I am currently using ifelse pointwise in a vector, but have a nagging
suspicion that there is a
2017 Dec 03
1
Discourage the weights= option of lm with summarized data
Peter,
This is a highly structured text. Just for the discussion, I separate
the building blocks, where (D) and (E) and (F) are new:
BEGIN OF TEXT --------------------
(A)
Non-?NULL? ?weights? can be used to indicate that different
observations have different variances (with the values in ?weights?
being inversely proportional to the variances);
(B)
or equivalently, when the elements of
2011 Feb 27
3
nested case-control study
Hi, I am wondering if there is a package for doing conditional logistic
regression for nested case-control study as described in "Estimation of absolute
risk from nested case-control data" by Langholz and Borgan (1997) where
Horvitz-Thompson sampling weight (log of (number in the risk set divided by the
number sampled)) is used with regression. In SAS Proc Phreg, this is implemented
2014 Oct 08
2
Optimización con restricciones lineales
Hola a todos,
Estoy intentando resolver un problema de optimización con R con
restricciones lineales, pero no consigo incluir dichas restricciones. Es
decir,
f<-function(w){
sd(...) # desviación típica de ciertos datos
}
optim(rep(1/2,8),fn = f,lower=0,upper=1,method='L-BFGS-B') # no se como
incluir aquí las restricciones
Las restricciones son: la suma de los w_i es 1 y todos los
2006 May 20
1
(PR#8877) predict.lm does not have a weights argument for newdata
Dear R developers,
I am a little disappointed that my bug report only made it to the
wishlist, with the argument:
Well, it does not say it has.
Only relevant to prediction intervals.
predict.lm does calculate prediction intervals for linear models from
weighted regression, so they should be correct, right?
As far as I can see they are bound to be wrong in almost all cases, if
no weights
2003 Dec 15
1
distribution of second order statistic
Hi,
I am getting some weird results here and I think I am missing something.
I am trying to program a function that for a set of random variables
drawn from uniform distributions plots that distribution of the second
order statistic of the ordered variables. (ie I have n uniform
distributions on [0, w_i] for w_i different w_j and i=1..n. I want to
plot the distribution of the second order
2009 May 07
2
lasso based selection for mixed model
Dear useRs (called Frank Harrell, most likely),
after having preached for years to my medical colleagues to be cautious
with stepwise selection procedures, they chanted back asking for an
alternative when using mixed models.
There is a half dozen laXXX packages around for all types of linear models,
but as far I see there is none for mixed models such as lme. Even
boot.stepAIC (which I
2012 Nov 24
6
IMPORTANT!!!! PLEASE HELP ME
Hi,
I want to generate 10000 samples from normal distribution with replacement
case and every sample size is 50. What should I do ?
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Sent from the R help mailing list archive at Nabble.com.
2017 Oct 12
4
Discourage the weights= option of lm with summarized data
OK. We have now three suggestions to repair the text:
- remove the text
- add "not" at the beginning of the text
- add at the end of the text a warning; something like:
"Note that in this case the standard estimates of the parameters are
in general not correct, and hence also the t values and the p value.
Also the number of degrees of freedom is not correct. (The parameter
2009 Aug 06
1
solving system of equations involving non-linearities
Hi,
I would appreciate if someone could help me on track with this problem.
I want to compute some parameters from a system of equations given a number of sample observations. The system looks like this:
sum_i( A+b_i>0 & A+b_i>C+d_i) = x
sum_i( C+d_i>0 & C+d_i>A+b_i) = y
sum_i( exp(E+f_i) * ( A+b_i>0 & A+b_i>C+d_i) = z
A, C, E are free variables while the other
2012 Mar 27
2
Supperscript, subscript and double lines in the main/sub title and using greek letters
Dear R-help,
I am trying to express myself as best as I can here. If you also use Latex
to edit math reports or other languages with similar editing method,
you'll see what I'm talking about. My sincere appologies if my question is
not clear enough to some extend, as also I'm not able to provide my code
here because I don`t know which one I can use...
When editing the title in R
2013 Feb 19
2
[LLVMdev] Is va_arg correct on Mips backend?
I check the Mips backend for the following C code fragment compile result. It seems not correct. Is it my misunderstand or it's a bug.
//ch8_3.cpp
#include <stdarg.h>
int sum_i(int amount, ...)
{
int i = 0;
int val = 0;
int sum = 0;
va_list vl;
va_start(vl, amount);
for (i = 0; i < amount; i++)
{
val = va_arg(vl, int);
sum += val;
}
va_end(vl);
2004 Feb 02
1
glm.poisson.disp versus glm.nb
Dear list,
This is a question about overdispersion and the ML estimates of the
parameters returned by the glm.poisson.disp (L. Scrucca) and glm.nb
(Venables and Ripley) functions. Both appear to assume a negative binomial
distribution for the response variable.
Paul and Banerjee (1998) developed C(alpha) tests for "interaction and main
effects, in an unbalanced two-way layout of counts
2013 Jun 12
2
survreg with measurement uncertainties
Hello,
I have some measurements that I am trying to fit a model to. I also
have uncertainties for these measurements. Some of the measurements
are not well detected, so I'd like to use a limit instead of the
actual measurement. (I am always dealing with upper limits, i.e. left
censored data.)
I have successfully run survreg using the combination of well detected
measurements and limits,
2005 Oct 29
2
LaTex error when creating DVI version when compiling package
Dear Listers,
I got this message when compiling a package:
* creating pgirmess-manual.tex ... OK
* checking pgirmess-manual.text ... ERROR
LaTex errors when creating DVI version.
This typically indicates Rd problems.
The message is quite explicit but I struggled a lot before understanding
that the trouble comes from a single file "selMod.rd" among 44 topics.
Even though I have