princomp - varimax - factanal
At 3:00 PM +0100 1/30/09, Alberto Maceda Veiga wrote:
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
Unfortunately, SPSS labels principal components as a factor model. It is not. So, extracting the first n factors by using factanal will give you a very different solution than the first n principal components.
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 factanal function. Does anybody know which are the instructions into R to do exactly the same of what I have done with SPSS???
To duplicate the SPSS analysis try using the psych package. The principal function in the psych package will extract the first n components (defaults to 1) and then by default rotate using varimax. library(psych) pc <- principal(my.data,n) #where n is the number components you want to extract Let me know if this matches the SPSS output. Bill
Thank you very much! [[alternative HTML version deleted]]
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