Displaying 20 results from an estimated 1000 matches similar to: "te( ) interactions and AIC model selection with GAM"
2013 Nov 25
4
lmer specification for random effects: contradictory reults
Hi All,
I was wondering if someone could help me to solve this issue with lmer.
In order to understand the best mixed effects model to fit my data, I
compared the following options according to the procedures specified in many
papers (i.e. Baayen
<http://www.google.it/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CDsQFjAA
2010 Sep 08
4
coxph and ordinal variables?
Dear R-help members,
Apologies - I am posting on behalf of a colleague, who is a little puzzled
as STATA and R seem to be yielding different survival estimates for the same
dataset when treating a variable as ordinal. Ordered() is used to represent
an ordinal variable) I understand that R's coxph (by default) uses the Efron
approximation, whereas STATA uses (by default) the Breslow. but we
2011 Mar 19
1
strange PREDICTIONS from a PIECEWISE LINEAR (mixed) MODEL
Hi Dears,
When I introduce an interaciton in a piecewise model I obtain some quite
unusual results.
If that would't take u such a problem I'd really appreciate an advise from
you.
I've reproduced an example below...
Many thanks
x<-rnorm(1000)
y<-exp(-x)+rnorm(1000)
plot(x,y)
abline(v=-1,col=2,lty=2)
mod<-lm(y~x+x*(x>-1))
summary(mod)
yy<-predict(mod)
2012 Oct 23
1
factor or character
Hi,
The program below work very well.
(snps = c('rs621782_G', 'rs8087639_G', 'rs8094221_T', 'rs7227515_A',
'rs537202_C'))
Selec = todos[ , colnames(todos) %in% snps]
head(Selec)
But, I have a data set with 1.000 columns and I need extract 70 to use
(like snps in command above).
This 70 snps are in a file. So I create a file to extract them with
2011 Apr 07
1
Automated Fixed Order Stepwise Regression Function
Greetings,
I am interested in creating a stepwise fixed order regression function. There's a function for this already called add1( ). The F statistics are calculated using type 2 anova (the SS and the F changes don't match SPSS's). You can see my use of this at the very end of the email.
What I want: a function to make an anova table with f changes and delt R^2.
I ran into
2010 Nov 15
1
Executing Command on Multiple R Objects
Hello Everyone -
I want to print a number of results from lme function objects out to a txt
file. How could I do this more efficiently than what you see here:
out2 <- capture.output(summary(mod2a))
out3 <- capture.output(summary(mod3))
out4 <- capture.output(summary(mod5))
out5 <- capture.output(summary(mod6))
out6 <- capture.output(summary(mod7))
2002 Dec 18
6
Can I build an array of regrssion model?
Hi,
I am trying to use piecewise linear regression to approximate a
nonlinear function. Actually, I don't know how many linear functions I
need, therefore, I want build an array of regression models to automate
the approximation job. Could you please give me any clue?
Attached is ongoing code:
rawData = scan("c:/zyang/mass/data/A01/1.PRN",
what=list(numeric(),numeric()));
len =
2003 Apr 28
2
stepAIC/lme problem (1.7.0 only)
I can use stepAIC on an lme object in 1.6.2, but
I get the following error if I try to do the same
in 1.7.0:
Error in lme(fixed = resp ~ cov1 + cov2, data = a, random = structure(list( :
unused argument(s) (formula ...)
Does anybody know why?
Here's an example:
library(nlme)
library(MASS)
a <- data.frame( resp=rnorm(250), cov1=rnorm(250),
cov2=rnorm(250),
2012 Jun 04
1
Chi square value of anova(binomialglmnull, binomglmmod, test="Chisq")
Hi all,
I have done a backward stepwise selection on a full binomial GLM where the
response variable is gender.
At the end of the selection I have found one model with only one explanatory
variable (cohort, factor variable with 10 levels).
I want to test the significance of the variable "cohort" that, I believe, is
the same as the significance of this selected model:
>
2013 Nov 25
0
R: lmer specification for random effects: contradictory reults
Dear Thierry,
thank you for the quick reply.
I have only one question about the approach you proposed.
As you suggested, imagine that the model we end up after the model selection
procedure is:
mod2.1 <- lmer(dT_purs ~ T + Z + (1 +T+Z| subject), data =x, REML= FALSE)
According to the common procedures specified in many manuals and recent
papers, if I want to compute the p_values relative to
2011 Nov 17
1
Log-transform and specifying Gamma
Dear R help,
I am trying to work out if I am justified in log-transforming data and specifying Gamma in the same glm.
Does it have to be one or the other?
I have attached an R script and the datafile to show what I mean.
Also, I cannot find a mixed-model that allows Gamma errors (so I cannot find a way of including random effects).
What should I do?
Many thanks,
Pete
--------------
2008 Dec 22
1
sem package fails when no of factors increase from 3 to 4
#### I checked through every 3 factor * 3 loading case.
#### While, 4 factor * 3 loading failed.
#### the data is 6 factor * 3 loading
require(sem);
cor18<-read.moments();
1
.68 1
.60 .58 1
.01 .10 .07 1
.12 .04 .06 .29 1
.06 .06 .01 .35 .24 1
.09 .13 .10 .05 .03 .07 1
.04 .08 .16 .10 .12 .06 .25 1
.06 .09 .02 .02 .09 .16 .29 .36 1
.23 .26 .19 .05 .04 .04 .08 .09 .09 1
.11 .13 .12 .03 .05 .03
2003 Feb 10
2
problems using lqs()
Dear List-members,
I found a strange behaviour in the lqs function.
Suppose I have the following data:
y <- c(7.6, 7.7, 4.3, 5.9, 5.0, 6.5, 8.3, 8.2, 13.2, 12.6, 10.4, 10.8,
13.1, 12.3, 10.4, 10.5, 7.7, 9.5, 12.0, 12.6, 13.6, 14.1, 13.5, 11.5,
12.0, 13.0, 14.1, 15.1)
x1 <- c(8.2, 7.6,, 4.6, 4.3, 5.9, 5.0, 6.5, 8.3, 10.1, 13.2, 12.6, 10.4,
10.8, 13.1, 13.3, 10.4, 10.5, 7.7, 10.0, 12.0,
2005 Feb 01
3
polynomials REML and ML in nlme
Hello everyone,
I hope this is a fair enough question, but I don’t have access to a copy
of Bates and Pinheiro. It is probably quite obvious but the answer might
be of general interest.
If I fit a fixed effect with an added quadratic term and then do it as
an orthogonal polynomial using maximum likelihood I get the expected
result- they have the same logLik.
2013 Nov 07
2
[LLVMdev] Register allocation limitations
Hi all.
if there is limitation for the registers to be used together in an
instruction, should i try to change it in the register allocation pass
or should i try it somewhere else??
example.
lets say we have to add 2 registers
addu rx ,ry ,rz
there is a limitation that says that the two regs that will be added they
can not have the same mod4
so we can add r1 , r2 but cannot add r1,r5.
2008 Aug 13
1
re placing default labels in lattice
Dear all,
I am having a little trouble deciphering how to change the default x-axis
labels in a lattice xyplot (or any type of lattice plot for that matter). I
have tried using the "demo("labels") function but the code is truncated at
precisely the wrong moment!
All I am trying to do is to add superscript to two of the labels for which i
tried using the expression function. It
2009 Feb 03
0
lm function
Hi,
I do not use R lenguage for programming, hence Im trying to understand how
are specified the models below. I been reading some webpages with
information about the notation in the "lm" function, but havent understand
exactly what does the ":" do. Can some one give me an explenation of the
models below so I can replicate the results in other program.
#common intercept
2008 May 09
1
Windows key works some times I boot, doesn't work others
Hi all,
I run CentOS5.1 with all updates, and like to use metacity's keybindings
(gconf-editor->/apps/metacity/global_keybindings and
keybinding_commands) to set shortcut keys for xterm, nautilus, and the
like, so <Mod4>x runs xterm and <Mod4>e runs nautilus, rather how
Windows-XP keyboard shortcuts work. I always log on as 'neek', the only
user other than
2005 Apr 18
2
Construction of a large sparse matrix
Dear List:
I'm working to construct a very large sparse matrix and have found
relief using the SparseM package. I have encountered an issue that is
confusing to me and wonder if anyone may be able to suggest a smarter
solution. The matrix I'm creating is a covariance matrix for a larger
research problem that is subsequently used in a simulation. Below is the
latex form of the matrix if
2018 Dec 02
2
[PATCH nbdkit v2] common: Move shared bitmap code to a common library.
This is exactly the same as v1:
https://www.redhat.com/archives/libguestfs/2018-December/msg00004.html
except that it now frees the bitmap on unload (which the old code did
not - there was always a memory leak).
Rich.