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princomp - varimax - factanal

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princomp - varimax - factanal

Alberto Maceda Veiga
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 factanal function.


Does anybody know which are the instructions into R to do exactly the same
of what I have done with SPSS???



Thank you very much!

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Re: princomp - varimax - factanal

ssefick
Maybe look into vegan - although this is not my area of specialty
(assuming I have one at all).
good luck


On Fri, Jan 30, 2009 at 9:00 AM, Alberto Maceda Veiga <[hidden email]> 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
>
> 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???
>
>
>
> Thank you very much!
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



--
Stephen Sefick

Let's not spend our time and resources thinking about things that are
so little or so large that all they really do for us is puff us up and
make us feel like gods.  We are mammals, and have not exhausted the
annoying little problems of being mammals.

                                                                -K. Mullis

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Re: princomp - varimax - factanal

William Revelle
In reply to this post by Alberto Maceda Veiga
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]]
>
>______________________________________________
>[hidden email] mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.


--
William Revelle http://personality-project.org/revelle.html
Professor http://personality-project.org/personality.html
Department of Psychology             http://www.wcas.northwestern.edu/psych/
Northwestern University http://www.northwestern.edu/
Attend  ISSID/ARP:2009               http://issid.org/issid.2009/

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Re: princomp - varimax - factanal

Alberto Maceda Veiga
In reply to this post by Alberto Maceda Veiga
Thank you very much Bill!!!  We get it. The results are the same.

Best wishes,

Alberto



2009/1/30 William Revelle <[hidden email]>

> 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]]
>>
>> ______________________________________________
>> [hidden email] mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>
> --
> William Revelle         http://personality-project.org/revelle.html
> Professor
> http://personality-project.org/personality.html
> Department of Psychology
> http://www.wcas.northwestern.edu/psych/
> Northwestern University http://www.northwestern.edu/
> Attend  ISSID/ARP:2009               http://issid.org/issid.2009/
>
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>


--
Alberto Maceda Veiga
Departamento de Biología Animal
Vertebrados. 1ª Planta. Despacho 151.
Facultad de Biología
Universidad de Barcelona
Av. Diagonal, 645
08028 Barcelona
Spain
Tel: 93 4021041
Fax: 93 4034426
Email: [hidden email]
><((((º>  ><((((º>  ><((((º>

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______________________________________________
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