Re: [R] PCA analysis and bootstraped loadings

2015-04-14 Thread Efstathia Defteraiou
Dear All, Thank You for the quick responses. Managed to solve my problem through: http://www.faculty.biol.ttu.edu/strauss/multivar/R/SamplePCABootstrap.R.txt or http://r.789695.n4.nabble.com/bootstrapped-eigenvector-method-following-prcomp-td877655.html Used the first one however, code is too long

Re: [R] PCA analysis and bootstraped loadings

2015-04-13 Thread William Revelle
psych does not currently have bootstrapped confidence intervals for loadings. That is a reasonable request and I will try to add it, perhaps in the “real soon now” version of 1.5.4 (almost finished), perhaps in the next release, Bill > On Apr 13, 2015, at 2:38 PM, stephen sefick wrote: > > H

Re: [R] PCA analysis and bootstraped loadings

2015-04-13 Thread stephen sefick
Hi, Please search the mailing list archives for this, or type bootstrapped PCA R into google. Please provide a minimal self-contained example of what you are trying to solve. Please read the posting guide that is referenced at the end of every email. kind regards, Stephen On Mon, Apr 13, 2015 at

[R] PCA analysis and bootstraped loadings

2015-04-13 Thread Efstathia Defteraiou
Dear All, I am relatively new in R. Im working with the 'psych' package and 'principal' function. I would like to know how to generate the bootstraped conf.intervals for loadings, looking for sth similar to setting 'n.iter' argument for the 'fa' function. If in 'psych' can't work and suggest

Re: [R] pca analysis: extract rotated scores?

2010-12-01 Thread Mark Difford
Hi He Zhang, >> Is the following right for extracting the scores? >> ... >> pca$loadings >> pca$score Yes. But you should be aware that the function principal() in package psych is standardizing your data internally, which you might not want. That is, the analysis is being based on the correla

Re: [R] pca analysis: extract rotated scores?

2010-12-01 Thread He Zhang
Hi, I am also doing PCA. Is the following right for extracting the scores? library(psych) pca<-principal(data,nfactors=,rotate="varimax",scores=T) pca$loadings pca$score Best regards, He On Tue, Nov 30, 2010 at 10:22 AM, Liviu Andronic wrote: > Dear all > I'm unable to find an example of extra

Re: [R] pca analysis: extract rotated scores?

2010-12-01 Thread Mark Difford
Hi Liviu, >> However, I'm still confused on how to compute the scores when rotations >> (such as 'varimax' or other methods in GPArotation) are applied. PCA does an orthogonal rotation of the coordinate system (axes) and further rotation is not usually done (in contrast to factor analysis). Nei

Re: [R] pca analysis: extract rotated scores?

2010-11-30 Thread Liviu Andronic
Take 2 on this. Below I'm pasting the code to perform PCA in R (without any rotation), manually; using ?princomp; and using ?principal. I also point out some differences in teh output and terminology of the two functions. In short, I found how to compute the scores of principal components when no r

[R] pca analysis: extract rotated scores?

2010-11-30 Thread Liviu Andronic
Dear all I'm unable to find an example of extracting the rotated scores of a principal components analysis. I can do this easily for the un-rotated version. data(mtcars) .PC <- princomp(~am+carb+cyl+disp+drat+gear+hp+mpg, cor=TRUE, data=mtcars) unclass(loadings(.PC)) # component loadings summary(

[R] PCA analysis, presence-absence of mammals in parks

2010-08-10 Thread zloutor
Hi everyone, So I am trying to see which ecological parameter of different parks in nyc influence the most the diversity of the medium-sized mammals in those parks. I have a bunch of different parameters for each park I'm done studying and the presence (1) and absence (0) of each mammal. I wanted

Re: [R] PCA analysis

2008-06-19 Thread Daniel Malter
n my samples are not in a correct order? As you realize I am quite new with R. Thank you so much for taking your time helping me, I really appreciate it. Regards, Monna > From: [EMAIL PROTECTED] > To: [EMAIL PROTECTED]; r-help@r-project.org > Subject: AW: [R] PCA analysis > Date: T

[R] PCA analysis

2008-06-18 Thread Monica Pisica
Monna, The way i do it is to re-create the biplot for the PCA . I am attaching my code (i am sure this can be done even easier . but this works as well) where i am using pca() function from labdsv and my data is called veg1. library (labdsv) pca.1<-pca(veg1,cor=TRUE) # The scores are

Re: [R] PCA analysis

2008-06-17 Thread Daniel Malter
-project.org Betreff: [R] PCA analysis Hi, I have a problem with making PCA plots that are readable. I would like to set different sympols instead of the numbers of my samples or their names, that I get plotted (xlabs). How is this possible? With points, i don4t seem to get the right data

[R] PCA analysis

2008-06-17 Thread Monna Nygård
Hi, I have a problem with making PCA plots that are readable. I would like to set different sympols instead of the numbers of my samples or their names, that I get plotted (xlabs). How is this possible? With points, i don´t seem to get the right data plotted onto the PCA plot, as I do not qu