Displaying 20 results from an estimated 4000 matches similar to: "AIC function and Step function"

2007 May 14

2

lmer function

Does anyone know if the lmer function of lme4 works fine for unbalanced designs? I have the examination results of 1000 pupils on three subjects, one score every term. So, I have three scores for English (one for every term), three scores for maths etc. However, not everybody was examined in maths, not everybody was examined in English etc, but everybody was in effect examined on four subjects. I

2005 Jan 26

2

Source code for "extractAIC"?

Dear R users:
I am looking for the source code for the R function extractAIC. Type the
function name doesn't help:
> extractAIC
function (fit, scale, k = 2, ...)
UseMethod("extractAIC")
<environment: namespace:stats>
And when I search it in the R source code, the best I can find is in (R
source root)/library/stats/R/add.R:
extractAIC <-

2010 Jun 16

3

mgcv, testing gamm vs lme, which degrees of freedom?

Dear all,
I am using the "mgcv" package by Simon Wood to estimate an additive mixed
model in which I assume normal distribution for the residuals. I would
like to test this model vs a standard parametric mixed model, such as the
ones which are possible to estimate with "lme".
Since the smoothing splines can be written as random effects, is it
correct to use an (approximate)

2005 Oct 24

2

GAM and AIC: How can I do??? please

Hello, I'm a Korean researcher who have been started to learn the "R"
package.
I want to make gam model and AIC value of the model to compare several
models.
I did the GAM model, but there were error for AIC.
SO, how can I do? pleas help me!!!
I did like below;
> a.fit <- gam(pi~ s(t1r), family = gaussian(link="log"))
>

2017 Jun 08

1

stepAIC() that can use new extractAIC() function implementing AICc

I would like test AICc as a criteria for model selection for a glm using
stepAIC() from MASS package.
Based on various information available in WEB, stepAIC() use
extractAIC() to get the criteria used for model selection.
I have created a new extractAIC() function (and extractAIC.glm() and
extractAIC.lm() ones) that use a new parameter criteria that can be AIC,
BIC or AICc.
It works as

2006 Apr 20

1

Extract AIC, BIC

Hi All,
How can extract AIC,BIC from a fitted Garch model?
--
SUMANTA BASAK.
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2004 Apr 02

2

How canI convert date-time to Julian date?

Hello!!
I need some help! I tried everything, but nothing worked!
I have a vector c with dates in it, in the format "2004-04-01" and i need to
convert it in the form
"04/01/2004" or "01/04/2004" !
How can i do that??
Thanks
Bye Martina
--

2010 Jan 26

1

AIC for comparing GLM(M) with (GAM(M)

Hello
I'm analyzing a dichotomous dependent variable (dv) with more than 100
measurements (within-subjects variable: hours24) per subject and more
than 100 subjects. The high number of measurements allows me to model
more complex temporal trends.
I would like to compare different models using GLM, GLMM, GAM and
GAMM, basically do demonstrate the added value of GAMs/GAMMs relative

2012 Feb 26

1

improved error message when existing implicit S4 generic is not imported?

pkgA's NAMESPACE has
importFrom(graphics, plot)
exportClasses("A")
exportMethods("plot")
R/foo.R has
setClass("A")
setMethod("plot", "A", function(x, y, ...) {})
During R CMD INSTALL pkgA_1.0.tar.gz we are told
** preparing package for lazy loading
Creating a generic function for 'plot' from package

2009 Jan 22

2

Is it possible for R to import a SigmaPlot file?

I recently received a Sigmaplot file (*.jnb) from a customer and would like to know if I can input it to a data frame and then manipulate the data in R.
I did a search on Google and on RSeek (www.rseek.org), but did not get any good hits. Thank for any feedback and insight you can provide.
P.S. Love the flexibility of R and would love to keep using it. Just wanting to know if this is

2009 Apr 29

12

Una pregunta de estadística (marginalmente relacionada con R)

Hola, ¿qué tal?
Tengo una pregunta de esta

2007 Apr 17

3

Extracting approximate Wald test (Chisq) from coxph(..frailty)

Dear List,
How do I extract the approximate Wald test for the
frailty (in the following example 17.89 value)?
What about the P-values, other Chisq, DF, se(coef) and
se2? How can they be extracted?
######################################################>
kfitm1
Call:
coxph(formula = Surv(time, status) ~ age + sex +
disease + frailty(id,
dist = "gauss"), data = kidney)

2010 Apr 14

1

Selecting derivative order penalty for thin plate spline regression (GAM - mgcv)

Hi,
I am using GAMs (package mgcv) to smooth event rates in a penalized regression setting and I was wondering if/how one can
select the order of the derivative penalty.
For my particular problem the order of the penalty (parameter "m" inside the "s" terms of the formula argument) appears to
have a larger effect on the AIC/deviance of the estimated model

2008 Apr 29

1

AIC extract and comparison

Hi, I need to fit models and use AIC method to campare the best fitted model
manually.
When i extract AIC by using extractAIC, it gave me the df and AIC values.
Now the problem is, how can I compare the AIC values from two models?
is there anyway to extract AIC with no df so that I can compare directly?
Thank you!
> extractAIC(coxout)
[1] 1.000 1723.038
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2009 Jan 14

2

coercing a list into matrix

Dear list,
I have a list of number sequences. Each number sequence has different
numbers of elements. Is there a quick way (other than to iterate
through the entire list) way to coerce list to matrix with NAs filling
in the short sequences?
An example of what I mean is this:
A <- list(c(3,2,3),c(6,5))
I'd like to get A so that it is
3 2 3
6 5 NA
Best,
Ken

2007 Mar 21

2

problem with RCurl install on Unix

I am having trouble getting an install of RCurl to work properly on a
Unix server. The steps I have taken are:
1. installed cUrl from source without difficulty
2. installed RCurl from source using the command
~/R_HOME/R-devel/bin/R CMD INSTALL -l ~/R_HOME/R-devel/library
~/RCurl_0.8-0.tar.gz I received no errors during this install
3. when I go back to R and

2007 Mar 21

2

problem with RCurl install on Unix

I am having trouble getting an install of RCurl to work properly on a
Unix server. The steps I have taken are:
1. installed cUrl from source without difficulty
2. installed RCurl from source using the command
~/R_HOME/R-devel/bin/R CMD INSTALL -l ~/R_HOME/R-devel/library
~/RCurl_0.8-0.tar.gz I received no errors during this install
3. when I go back to R and

2010 Sep 22

2

speeding up regressions using ddply

Hi,
I have a data set that I'd like to run logistic regressions on, using
ddply to speed up the computation of many models with different
combinations of variables. I would like to run regressions on every
unique two-variable combination in a portion of my data set, but I
can't quite figure out how to do using ddply. The data set looks like
this, with "status" as

2009 Mar 30

1

what is R equivalent of Fortran DOUBLE PRECISION ?

I noticed taht R cannot understand certain Fortran real constant formats. For instance:
c14 <- as.double( 7.785205408500864D-02)
Error: unexpected symbol in " c14 <- as.double( 7.785205408500864D"
The above "D" is used in Fortran language to indicate the memory starage mode. That is for instructing Fortran compiler
to store such a REAL constant in DOUBLE

2004 Dec 04

1

AIC, AICc, and K

How can I extract K (number of parameters) from an AIC calculation, both to
report K itself and to calculate AICc? I'm aware of the conversion from AIC ->
AICc, where AICc = AIC + 2K(K+1)/(n-K-1), but not sure of how K is calculated
or how to extract that value from either an AIC or logLik calculation.
This is probably more of a basic statistics question than an R question, but I