Displaying 20 results from an estimated 21 matches for "difr".
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2012 Mar 04
1
Could not compute QR decomposition of Hessian.
...sem.default(ram = ram, S = S, N = N, param.names = pars, var.names =
vars, :
Could not compute QR decomposition of Hessian.
Optimization probably did not converge.
######### Model ########
mDPDF =
data.frame(mj1,mj2,mj3,mj4,mj5,eL1,eL2,eL3,eL4,eL5,aC1,aC2,aC3,aC4,disR1,disR2,disR3,disR4,disR5,
difR1,difR2,difR3,difR4,difR5,difR6,dC1,dC2,dC3,dC4,aB1,aB2,aB3,aB4,aB5,deh1,deh2,deh3,deh4)
mydata.cov <- cov(mDPDF)
model.mydata <- specify.model()
MJ -> mj1, NA, 1
MJ -> mj2, lam2, NA
MJ -> mj3, lam3, NA
MJ -> mj4, lam4, NA
MJ -> mj5, lam5, NA
EL -> eL1, NA, 1
EL -> eL2, la...
2007 Oct 01
2
non-linear model parameterization
...parameter estimates.
What I am interested in is to make inference about parameters b and g, so this has to be taken into account in the model formulation.
What options do I have?
Also, how is it possible to fit a partially linear model?
Thank you!!
Irene Mantzouni
----------------
PhD student
DIFRES
2008 Feb 18
3
mean and variance of ratio
Hi all!
I try to estimate a statistic of the form: (x1-x2)/(y1-y2), where
x1,x2,y1,y2 represent variable means, so each has an estimate and
standard error associated with it.
How is it possible to estimate the mean and the variance of this ratio?
Thank you!
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2007 Jun 21
3
meta-analysis in R
I would like to combine time-series data to test for correlations and
interactions using random and fixed effects meta-analysis.
So, I am looking for the right packages and documentation.
I know about meta and rmeta packages of R.
Are there any more? What are the diffrences in brief?
Can you please suggest some references that could be used as a guide for
meta-analysis in R (or S-plus)?
2007 Nov 04
1
hierarchical mixed model
I would like to fit a 2-level mixed model:
yit=a+a[i]+a[it] +(b+b[i]+b[it])*xit+eps[it]
However, the variance of the second level components should depend on the group, i.e. sigma for a[it] and b[it] should be [i] specific.
I do not know whether this is conceptually right in the mixed model context...
In case it stands, how should the formula look like?
Also, the data are unbalanced with
2008 Feb 19
1
regression with error in predictor
Hi all!
I am trying to run a regression where the predictor values are not real
data but each is estimated from a different model. So, for each value I
have a mean and variance.
Which package/function should I use in this case?
Thank you!
Irene
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2007 Sep 21
1
Error: (subscript) logical subscript too long
As part of a larger program I have a rather long and involved sub-procedure which fails to work, It manipulates some large matrices, stored to the disc. The procedure halts with the message:
Error: (subscript) logical subscript too long
Can anyone give advice about what may cause this error and how it can be remedied - I feel confident that it is not a syntactically or logical error.
Thanks,
2010 Jul 21
0
DIF Analysis starting from a gpcm class object
Dear useRs,
does any of you have suggestions on how to conduct a proper DIF analysis
starting from a model of
class gpcm (from the wonderful package ltm by prof. Rizopoulos)?
difR will handle only dichotomous items, and I have a mix of dicho- and
polytomous ones (that's why I chose the partial credit model).
I also found the package lordif, but I'm not really sure if that's what I
need.
I basically want to regress item difficulties on some other covariates (se...
2007 Oct 09
5
continue for loop in case of erros
Dear all,
I have a for loop which includes nls model estimation.
The loop breaks after the first non-convergence error.
How can I make the loop continue and try to estimate all models?
I suppose it should be sth like: if(...) { next }
but I have no idea how to setup the arguements...
Thank you!
Irene
2009 Sep 27
3
CRAN (and crantastic) updates this week
...essandra R. Brazzale
http://crantastic.org/packages/csampling
Monte Carlo conditional inference for the parameters of a linear
nonnormal regression model
* desire (1.0.5)
Olaf Mersmann
http://crantastic.org/packages/desire
Harrington and Derringer-Suich type desirability functions
* difR (1.0)
Sebastien Beland
http://crantastic.org/packages/difR
The difR package contains several traditional methods to detect DIF in
dichotomously scored items. Both uniform and non-uniform DIF effects
can be detected, with methods relying upon item response models or
not. Some methods de...
2010 Jul 27
3
Checking package licences including dependencies?
I only recently discovered options("available_packages_filters" =
list(add = TRUE, "license/FOSS")) [cf. help("available.packages",
package="utils") in R 2.10.0 or later] which goes nicely with my
options("checkPackageLicense" = TRUE) [new in R 2.11].
But now I want to purge my library of packages I would not have
installed had I known about
2009 Dec 13
3
CRAN (and crantastic) updates this week
CRAN (and crantastic) updates this week
New packages
------------
* Bergm (1.0)
Alberto Caimo
http://crantastic.org/packages/Bergm
Functions implementing Bayesian estimation for exponential random
graph models via exchange algorithm
Updated packages
----------------
lmtest (0.9-26), logcondens (1.3.5), MTSKNN (0.0-4), pmml (1.2.21),
r2lUniv (0.9.4), rattle (2.5.11), rgdal (0.6-23),
2012 Mar 11
1
CRAN (and crantastic) updates this week
CRAN (and crantastic) updates this week
New packages
------------
* EffectStars (1.0)
Maintainer: Unknown
Author(s): Gunther Schauberger
License: GPL-2
http://crantastic.org/packages/EffectStars
The package provides functions to visualize regression models with
categorical response. The effects of the covariates are plotted with
star plots in order to allow for an optical
2010 Jul 18
6
CRAN (and crantastic) updates this week
...uster (1.13.1), clusterSim (0.38-1), cmprskContin (1.6),
coarseDataTools (0.2), coin (1.0-12), copula (0.9-7), corrplot (0.30),
cshapes (0.2-4), ctv (0.6-0), cudaBayesreg (0.3-6), dagR (1.1.1),
data.table (1.4.1), dclone (1.1-0), ddesolve (1.04), denstrip (1.5),
depmixS4 (0.9-0), DiceKriging (1.1), difR (3.1), distr (2.2.3),
diveMove (1.0), dlnm (1.2.4), doBy (4.0.6), doMC (1.2.1), dplR
(1.3.5), drc (1.9-3), dti (0.9-2), eba (1.5-7), elrm (1.2.1), emplik2
(1.10), ensembleBMA (4.5), epicalc (2.11.1.0), epitools (0.5-6), eqtl
(1.1), eRm (0.13-0), exact2x2 (1.0-1), exactci (1.1-0), extremevalues
(2.1...
2007 Feb 15
0
FW: simpleR or usingR package by Verzani
I am a new R user and so I thought I could start with "Using R for
Introductory statistics" by Verzani.
In order to use some of the functions and datasets I have to install the
simpleR package which is is now inside the UsingR package. I did so
using
>install.packages("UsingR"). However, the functions such as
"simple.freqpoly.R" do not work.
I also tried to
2007 Oct 07
1
constructing a self-starting non-linear model
Dear all,
I am trying to define a selfStart function for a non-linear model, which is a log-transformed SSmicmen model with multiplicative errors and so it is required to make them additive:
log(y)=log(a)+log(x)-log(1+x/b)
Any ideas about how to use the "peeling" method to derive the "initial" argument and get the initial values?
Thank you for being always there!:)
2007 Oct 15
2
coef se in lme
Hi all!
How is it possible to estimate standard errors for coef obtained from lme?
Is there sth like se.coef() for lmer or what is the anaytical solution?
Thank you!
2007 Nov 28
1
interaction of continuous terms
Hi all!
this is a rather statistical question:
is it meaningful to consider an interaction effect between 2 continuous covariates?
for example: lm(y~x1+x2+x1:x2)
Should one of continuous x1, x2 be "transformed" to a categorical variable, i.e. be classified into groups?
Is it easier to interpret the effect if 1 or both are centered to the mean or z-transformed?
Thank you!
2007 Nov 07
1
mixed model testing
Is there a formal way to prove the need of a mixed model, apart from e.g. comparing the intervals estimated by lmList fit?
For example, should I compare (with AIC ML?) a model with seperately (unpooled) estimated fixed slopes (i.e.using an index for each group) with a model that treats this parameter as a random effect (both models treat the remaining parameters as random)?
Thank you!
2007 Apr 27
1
Inflate/Expand/Resize an array
Gudday,
I've had a good look everywhere trying to figure out how to do this, but
I'm afraid I can seem to find an answer anywhere - maybe its because I'm
not using the right terms, or maybe its because I'm a dummy. But
unfortunately, I am not completely and utterly stuck. Here's the
problem:
I have two large, six dimensional arrays that I would like to add
together. Lets call