Displaying 20 results from an estimated 6000 matches similar to: "customer segmentation using a large data with many zeros"
2007 Sep 07
5
SQL like function?
Hi RUsers,
I am wonder if I can search observations whose IDs matches any of the
values in another vector, such as in MySQL. While I am learing MySQL for
future database management, I appreciate if anyone could give me a hint.
Suppose I have one 5*1 vector containing observation IDs and
frequencies, and one 3*1 vector containing observation IDs.
observation<-c(1,2,3,4,5)
ID<-c(1,3,4)
2012 Jun 29
1
Help for string opeation
Hi R users,
I appreciate if you could give me some hint/help on this string operation.
Suppose I have a list of string objects in varying sizes like
[[1]]
[1] "A" [2] "B" [3] "C"
[[2]]
[1] "D" [2] "E"
[[3]]
[1] "F"
Then I would like to create a vector that contains all elements like
[1] "A" "B" "C"
2007 Dec 24
2
R Compilation error on Ubuntu
Hi
I bought a new laptop HP dv9500 just a week ago and installed a Ubuntu
gutsy ribbon on this laptop. I wanted to install Fedora but there are
more threads on Ubuntu, so I decided to install Ubuntu. After hours of
struggle in configuring x server/graphic card stuff, I installed R for
Gutsy ribbon using "sudo apt-get install g77 r-core'.
Now when I tried to install 'sp' package
2007 May 10
1
A simple question about PRINCOMP
Hi,
I just wonder if this is a rounding error by the princomp command in R.
Although this does not make much sense, using a hypothetical dataset, a,
a<-matrix(runif(1000),100,10)
I did PCA with the princomp, and compared it with the results estimated
with the eigen and the prcomp commands. And I found some differences in
the results: opposite signs in the loadings; slight differences in
2007 Sep 08
2
Problem in installing packages on linux machine...
Hi,
I am trying to install RSQLite package on my Fedora workstation. I
tried to install other packages as well, but each time I got the same
error messages saying "compilation error" and "non zero exit status".
Do I have to specify "lib="? I never specified the library path before
when I was using Fedora Core 6.
Warning in install.packages("RSQLite")
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
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
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
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
2012 Oct 02
0
Error messages when attempting to calculate polychoric correlation matrices using the psych package
Dear Professor Fox,
Apologies for my oversight relating to the polychor command and thank you for your advice. I turned to the polychor command when trying to find an equivalent for the polychoric command found in the psych package (I am following a procedure outlined in Gadermann, Guhn & Zumbo, 2012 that uses this command rather than the polycor package) . The polychoric command is returning
2013 Nov 28
0
polychoric correlation with multiple imputations, a Strate and a Weight
Hi there,
I'm generally more a Stata user than a R user, but I need to computed
something, and I am not able to do it with Stata 13. So, here I am!
I have a database that has multiple imputations (imputations are already
done) with a complex sample design (Strate and Weight).
Is it possible, in R, to run polychoric correlation with multiple
imputation, a Strate and a Weight ?
For the
2013 Dec 17
1
Polychoric Principal Component Analysis (pPCA)
I have data set with binary responses. I would like to
conduct polychoric principal component analysis (pPCA). I know there are several packages used in PCA but I could not find one that directly estimate pPCA and graph the individuals and variables maps. I will appreciate any help that expand these reproducible scripts.
#How to conduct polychoric principal component analysis pPCA using
#either
2009 Feb 02
1
Fit indexes in SEM with categorical data + ML estimation
Hello,
It has been found that SEM analysis using polychoric correlations + maximum
likelihood estimator produces incorrect test statistics and standard errors
(e.g., Flora, D. B., & Curran, P. J. (2004). An Empirical Evaluation of
Alternative Methods of Estimation for Con?rmatory Factor Analysis With
Ordinal Data. Psychological Methods, 9(4), 466-491).
Standard errors can be dealt with by
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 =
2004 Dec 03
0
New package: polycor
Dear list members,
I've uploaded a new package, called polycor (version 0.5-0), to CRAN. The
package has functions for computing polychoric and polyserial correlations,
either by maximum-likelihood (in which case, standard errors are available)
or by faster approximations. There's also a function to compute
"heterogeneous" correlation matrices composed of product-moment,
2004 Dec 03
0
New package: polycor
Dear list members,
I've uploaded a new package, called polycor (version 0.5-0), to CRAN. The
package has functions for computing polychoric and polyserial correlations,
either by maximum-likelihood (in which case, standard errors are available)
or by faster approximations. There's also a function to compute
"heterogeneous" correlation matrices composed of product-moment,
2006 Jan 19
0
Editing Partial Correlation Matrix
Hi,
I created a matrix of correlation coefficients and their respective scatterplots using the commands hetcor() and panel.cor(). Can I edit this matrix? I would like to have the scale values display at the top, as opposed to the alternating top-bottom scale approach. Also, I would like to increase the font size of the graphic for print purposes. Any help on how to accomplish this would be
2008 Feb 04
1
how to get points from SpatialPolygonsDataFrame
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2010 Mar 14
3
CRAN (and crantastic) updates this week
CRAN (and crantastic) updates this week
New packages
------------
* apcluster (1.0.1)
Ulrich Bodenhofer
http://crantastic.org/packages/apcluster
The apcluster package implements Frey's and Dueck's Affinity
Propagation clustering in R. The algorithms are analogous to the
Matlab code published by Frey and Dueck.
* BioPhysConnectoR (1.6-1)
Franziska Hoffgaard
2006 Aug 04
1
polychoric correlation error
Dear all,
I get a strange error when I find polychoric correlations with the ML method, which I have been able to reproduce using randomly-generated data.
What is wrong?
I realize that the data that I generated randomly is a bit strange, but it is the only way that I duplicate the error message.
> n<-100
> test.x<-rnorm(n, mean=0, sd=1)
> test.c<-test.x + rnorm(n, mean=0,