Displaying 20 results from an estimated 1000 matches similar to: "polychoric correlation error"
2006 Aug 21
2
polychor error
Hi.
Does anyone know whether the following error is a result of a bug or
a feature?
I can eliminate the error by making ML=F, but I would like to see the
values of the cut-points and their variance.
tmp.vec<-c(0, 0, 0 , 0 ,0 , 1, 0, 2, 0 , 0, 5 ,5 ,3 ,1,
0 , 1, 5, 10, 27, 20, 9, 0, 1, 1, 12, 29, 57, 34, 0, 0, 1,
2, 11, 31, 32)
tmp.mat<-matrix(tmp.vec, nrow=7)
2009 Jan 12
3
polychoric correlation: issue with coefficient sign
Hello,
I am running polychoric correlations on a dataset composed of 12 ordinal and
binary variables (N =384), using the polycor package.
One of the association (between 2 dichotomous variables) is very high using
the 2-step estimate (0.933 when polychoric run only between the two
variables; but 0.801 when polychoric run on the 12 variables). The same
correlation run with ML estimate returns a
2007 Dec 19
1
Correlation when one variable has zero variance (polychoric?)
Hi,
I'm running this for a simulation study, so many combinations of parameter
produce many predictions that I need to correlate with data.
The problem
----------------
I'm using rating data with 3 to 5 categories (e.g., too low, correct, too
high). The underlying continuous scales should be normal, so I chose the
polychoric correlation. I'm using library(polychor) in its
2004 Nov 28
2
Tetrachoric and polychoric ceofficients (for sem) - any tips?
About two years ago there was a thread about this which suggested that at
that time nobody had these coefficients ready to go.
(a) has anyone in the meanwhile programmed them?
(b) I think I can see how to do the tetrachoric one with mvtnorm on similar
lines to an example on the help page so will try that if nobody else
already has
(c) looking at the polychoric one makes me realise yet again
2012 Dec 07
1
Polychor() - why does it take that long?
Hello.
Using the polychor function
> polychor(data[c(s1,s2)] )
for polychoric correlations of two ordinal variables in R takes a long time
for N=7000 (20 minutes+) and significantly slows down my computer.
Now, I have a pretty old computer, but it takes about 20 seconds for MPLUS
to print out the complete polychoric correlation matrix for all 16
variables, while I am running the R function
2006 Jun 23
2
Tetrachoric correlation in R vs. stata
I hope someone here knows the answer to this since it will save me from
delving deep into documentation.
Based on 22 pairs of vectors, I have noticed that tetrachoric
correlation coefficients in stata are almost uniformly higher than those
in R, sometimes dramatically so (TCC=.61 in stata, .51 in R; .51 in
stata, .39 in R). Stata's estimate is higher than R's in 20 out of 22
2012 Oct 01
1
Error messages when attempting to calculate polychoric correlation matrices
Dear R users,
I am a psychology postgraduate student who is relatively new to using R. I am currently developing a psychometric scale and have run into a few problems when using R to calculate a polychoric correlation matrix for my dataset. I am trying to produce a polychoric correlation matrix for calculating ordinal reliability estimates (eg. Alpha, omega).The set consists of 439 observations
2004 Dec 09
1
Re: Tetrachoric and polychoric correlations, Polycor package
A bit late, but you might like to look at
http://www.qimr.edu.au/davidD/polyr.R
Regarding the original posters queries:
You can analyse polychoric correlations as if they were Pearson
correlations using standard software (eg sem), and this usually doesn't do
too badly, or go to AWLS (Browne) in LISREL etc, or ML analysis
of the full multidimensional contingency table using programs such as
2006 Oct 19
2
How to get multiple Correlation Coefficients
Hi
I have used a polycor package for categorical correlation coefficients.
I run the following script. But there were no results.
Could you tell me how to correct the script?
Thanks in advance,
vars <- names(sdi)
for (i in 1:length(vars)) {
for (j in 1:length(vars)) {
paste(vars[i]," and ", vars[j])
polychor(vars[i], vars[j])
# corr
}
}
--
Kum-Hoe Hwang, Ph.D.Phone :
2008 Sep 01
1
Polychoric and tetrachoric correlation
Hi there,
Am I correct to believe that tetrachoric correlation is a special case
of polychoric correlation when there are only two levels to the ordered
factor? Thus it should be okay to use hetcor from the polycor package
to build a matrix of correlations for binary variables?
If this is true, how can one estimate 95% confidence intervals for the
correlations? My guess would be
mat =
2010 Apr 02
2
tetrachoric correlations
Hi,
Is there any R library/package that calculates tetrachoric correlations from given marginals and Pearson correlations among ordinal variables?
Inputs to polychor function in polycor package are either contingency tables or ordinal data themselves. I am looking for something that takes marginal distributions and Pearson correlation as inputs.
For example, Y1=(1,2,3) with P(Y1=1)=0.3,
2013 Jul 01
1
Missing data problem and ROC curves
Hello all,
Trying to get this piece of code to work on my data set. It is from
http://www.itc.nl/personal/rossiter.
logit.roc <- function(model, steps=100)
{
field.name <- attr(attr(terms(formula(model)), "factors"),
"dimnames")[[1]][1]
eval(parse(text=paste("tmp <- ", ifelse(class(model$data) == "data.frame",
"model$data$",
2007 Apr 18
1
[Bridge] bridge at start up
hi i have gone through the achieves but still could not get my bridge to suvive a reboot .
please can anyone help me am using fedora core 2
-----Original message-----
From: bridge-request@lists.osdl.org
Date: Fri, 28 Jan 2005 03:08:06 +0100
To: bridge@lists.osdl.org
Subject: Bridge Digest, Vol 17, Issue 25
> Send Bridge mailing list submissions to
> bridge@lists.osdl.org
>
>
2006 Nov 12
2
Need help in waveslim package: imodwt and universal.thresh.modwt
Hi:
I have encountered problems with imodwt and universal.thresh.modwt and cannot find any reference in R Search. Hope someone can give me some ideas:
Starting with
modwt.la8 <- modwt(xdata, "la8", n.level=6) <-- this seems to work fine
(1) ydata <- imodwt(modwt.la8)
will always give ydata as numeric(0) (no values) instead of being a time series data with
2007 Jul 13
2
nearest correlation to polychoric
Dear all,
Has someone implemented in R (or any other language)
Knol DL, ten Berge JMF. Least-squares approximation of an improper correlation matrix by a proper one. Psychometrika, 1989, 54, 53-61.
or any other similar algorithm?
Best regards
Jens Oehlschl?gel
Background:
I want to factanal() matrices of polychoric correlations which have negative eigenvalue. I coded
Highham 2002
2006 Jul 30
1
Parametric links for glm?
At useR 2006 I mentioned that it would be nice to have a way to
specify binomial links
that involved free parameters and described some experience with a
Gosset link involving
a free degrees of freedom parameter, and a Tukey-lambda link with two
free parameters.
My implementation of this involved some rather kludgey modifications
of binomial,
make.link and glm that (essentially) added a
1999 May 20
1
Wavethresh + accessC > Error: wd.structure has no class
Hi,
Whenever I issue this commands (as in the help for the threshold
function),
#
# Do a 1D decomposition
#
tdecomp <- wd(test.data)
#
# Threshold it
#
tdecomp.thresh <- threshold(tdecomp)
#
# Reconstruct from the thresholded coefficients
#
trecons <- wr(tdecomp.thresh)
#
#
2001 Oct 08
3
testing diff for slopes and intercepts
I fit the model
fit<-lm(thresh~cond*Ne)
where
thresh is the reponse
cond is a factor with levels a, b, and c
Ne is a continuous indep var
I think of this full model as having three lines: thresh as a function of
Ne for each condition. Thus we have slopea, slopeb, slopec, inta, intb,
intc.
lm output my params
-------------------------
(Intercept) inta
condb intb - inta
condc
2006 Nov 15
2
??: Re:??: Re: Need help in waveslim package: imodwt and universal.thresh.modwt
Airon,
I don't think you have to find an English computer 'cause the
following must work in your Chinese one :-)
Let me explain. First of all, change your lines to
xdata <- ckhdat$Adj..Close[1:1447]
#names(ckhdwt.la8) <- c("w1", "w2", "w3", "w4", "w5","w6", "v6")
note the # sign, i.e., DO NOT change the names
2001 Nov 25
3
Win2k Printing Problem
I have a problem with Windows 2000 (SP2) printing to an Epson C60 on a
Linux server (running Mandrake 8.1 and Samba 2.2.2 with Cups 1.1.12). I've
scoured the net and posts on Usenet have not yielded any helpful response.
I have 2 Win2k boxes and they both respond differently, but neither is
printing. I've installed the printer on both boxes. On one I get a
"unable to