Displaying 20 results from an estimated 3000 matches similar to: "Factor Analysis function source code required"
2009 Mar 31
3
Factor Analysis Output from R and SAS
Dear Users,
I ran factor analysis using R and SAS. However, I had different outputs from
R and SAS.
Why they provide different outputs? Especially, the factor loadings are
different.
I did real dataset(n=264), however, I had an extremely different from R and
SAS.
Why this things happened? Which software is correct on?
Thanks in advance,
- TY
#R code with example data
# A little
2008 Sep 09
1
Addendum to wishlist bug report #10931 (factanal) (PR#12754)
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Hi,
on March 10 I filed a wishlist bug report asking for the inclusion of
some changes to factanal() and the associated print method. The changes
were originally proposed by John Fox in 2005; they make print.factanal()
display factor correlations if factanal() is called with rotation =
2009 Jan 30
3
princomp - varimax - factanal
Hi!
I am trying to analyse with R a database that I have previously analysed
with SPSS.
Steps with SPSS:
Factorial analysis
Extraction options : I select = Principal component analysis
Rotation: varimax
Steps with R:
I have tried it with varimax function with factanal or with princomp...and
the results are different of what I have with SPSS. I think that varimax
function is incorporated in
2010 May 06
1
how to get components / factors in factanal / princomp not loadings
Dear all,
i wonder if there?s a command to obtain the actual values of a principal component or a factor (not as.factor, but factanal) .
test=princomp(USArrests, cor = TRUE)
summary(test)
just outputs, standard deviation, Prop of Variance and cumulative proportion of variance.
test$loadings offers yet another proportion of variance scheme. why is that?
Apart from that:
Is there a
2009 Mar 25
2
pca vs. pfa: dimension reduction
Can't make sense of calculated results and hope I'll find help here.
I've collected answers from about 600 persons concerning three
variables. I hypothesise those three variables to be components (or
indicators) of one latent factor. In order to reduce data (vars), I
had the following idea: Calculate the factor underlying these three
vars. Use the loadings and the original var
2005 Oct 13
2
varimax rotation difference between R and SPSS
Hi,
I am puzzeled with a differing result of princomp in R and FACTOR in
SPSS. Regarding the amount of explained Variance, the two results are
the same. However, the loadings differ substantially, in the unrotated
as well as in the rotated form.
In both cases correlation matrices are analyzed. The sums of the squared
components is one in both programs.
Maybe there is an obvious reason, but I
2005 Nov 22
1
SPSS-like factor analysis procedure
I've read through many postings about principle component analysis in
the R-help archives, but haven't been able to piece together the
information I need. I'd like to recreate an SPSS-like experience of
factor analysis using R. Here's what SPSS produces:
1. Scatterplots of all possible variable pairs, with regression lines.
xyplot(my.dataframe) is perfect but for the lack of
2007 May 13
1
factanal
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2011 Jan 26
1
Factor rotation (e.g., oblimin, varimax) and PCA
A bit of a newbee to R and factor rotation I am trying to understand
factor rotations and their implementation in R, particularly the
GPArotation library.
I have tried to reproduce some of the examples that I have found, e.g., I
have taken the values from Jacksons example in "Oblimin Rotation",
Encyclopedia of Biostatistics
2010 Nov 30
3
pca analysis: extract rotated scores?
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(.PC) # proportions of variance
mtcars$PC1 <- .PC$scores[,1] # extract un-rotated scores of
2006 Apr 16
1
How to do varimax rotation for principal component based factor analysis, any packages?
Dear R users
the factanal pacakge is always MLE, which package can do varimax
rotation with the results from princomp ?
thank you
yong
2009 Aug 11
3
loadings function (PR#13886)
Full_Name: Mike Ulrich
Version: 2.9
OS: Mac OSX
Submission from: (NULL) (69.169.178.34)
The help documentation for loadings() lists more then one parameter. The
function call only expects one parameter. The digits, cutoff, and sort
parameters are not used in the function.
## S3 method for class 'loadings':
print(x, digits = 3, cutoff = 0.1, sort = FALSE, ...)
## S3 method for class
2004 Feb 17
1
varimax rotation in R
Hi everyone-
I have used several methods to calculate principal components rotated using the varimax procedure. This is simple enough. But I would like to calculate the % of variance explained associated with each PC before and after rotation.
factanal returns the % of variance explained associated with each PC but I cannot seem to get it to change after rotation.
Many thanks for your
2011 Mar 03
2
PCA - scores
I am running a PCA, but would like to rotate my data and limit the
number of factors that are analyzed. I can do this using the
"principal" command from the psych package [principal(my.data,
nfactors=3,rotate="varimax")], but the issue is that this does not
report scores for the Principal Components the way "princomp" does.
My question is:
Can you get an
2004 Nov 03
2
Princomp(), prcomp() and loadings()
In comparing the results of princomp and prcomp I find:
1. The reported standard deviations are similar but about 1% from
each other, which seems well above round-off error.
2. princomp returns what I understand are variances and cumulative
variances accounted for by each principal component which are
all equal. "SS loadings" is always 1.
3. Same happens
2007 Feb 06
3
How-To construct a cov list to use a covariance matrix in factanal?
Hi,
I have a set of covariance matrices but not the original data. I want to carry out some exploratory factor analysis. So, I am trying to construct a covariance matrix list as the input for factanal. I can construct a list which includes the cov, the centers, and the n.obs. But it doesn't work. I get an error that says "Error in sqrt(diag(cv)) : Non-numeric argument to mathematical
2006 Mar 15
3
Help on factanal.fit.mle
Hi
Can anybody please suggest me about the documentation of "factanal.fit.mle()"
(Not factanal()------ searching factanal.fit.mle() in R always leads to
factanal()).
Is there any function for doing principal component factor analysis in R.
Regards
Souvik Bandyopadhyay
JRF,
Dept Of Statistics
Calcutta University
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2003 May 01
0
factanal
# I have a question about how factanal is calculating the regression factor
# scores based on an oblique rotation (promax) of the factors.
#
# As is explained in the help file, regression factor scores are
# obtained as
#
# hat f = Lambda' Sigma^-1 x
#
# However, according to Harman's "Modern Factor Analysis" (e.g. second
# edition, pp. 351-352) the formula is
#
# hat f = Phi
2008 Jan 06
2
how to get residuals in factanal
In R factanal output, I can't find a function to give me residuals e.
I mannually got it by using x -lamda1*f1 -lamda2*f2 - ... -lamdan*fn, but the e
I got are not uncorrelated with all the f's.
What did I do wrong? Please help.
Yijun
____________________________________________________________________________________
Be a better friend, newshound, and
2009 Jan 13
1
PCA loadings differ vastly!
hi, I have two questions:
#first (SPSS vs. R):
I just compared the output of different PCA routines in R (pca, prcomp,
princomp) with results from SPSS. the loadings of the variables differ
vastly! in SPSS the variables load constantly higher than in R.
I made sure that both progr. use the correlation matrix as basis. I
found the same problem with rotated values (varimax rotation and rtex=T