Re: factor Analysis

[Huxley]

Thank you for explanation. Bu my question was unclear therefore let me ask
again. I invented an exapmle.

I have 10 questions in a questionnaire. These questions are my 10 variables.
A consumers fill this questionnaire for each 15 products e.g cars. Because
10 variables (X1, X2, ...,X10) are correlated with each other I use factor
analysis and (for convinence I ordered it) I get
Factor1: X1,X2,X3,X4,X5,X6,X7
Factor2: X8,X9,X10

I can  e.g put X1 into 2-D space, because I know that
X1= -1*F1+ (-1*F2). It means that X1 has co-ordinates X1=(-1,-1).
It's simple. But I'm not interested in positioning X1. For me it's important
where there are products (cars) in 2-D space. Therefore my question is how
to do it. I heard (but I do not know) that using e.g variable X1,...X10
mean and factor loadings I can do it i.e. for car1: I multiple  factor
loadings and variables mean (suitable) and I get this position
Could you help me verify this?
I would be very appreciate

Regards
Huxley

Uzytkownik John Uebersax [EMAIL PROTECTED] napisal w wiadomosci
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 A program like SAS or SPSS will calculate factor scores for you.  A
 factor score is an estimated location of an object (not a variable)
 relative to a factor.  If your factors are orthogonal, then you can
 plot each case using that case's score on Factor 1 and the score on
 Factor 2 as the X- and Y- coordinates of in a 2-dimensional space.

 I believe the formula for estimating factor scores of a common-factor
 model is not trvial (unless all communalities are 1).  Therefore one
 might as well let the software calculate factor scores.  The topic is
 well explained in the SAS manual (PROC FACTOR)--perhaps also in the
 SPSS manual.

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 Huxley [EMAIL PROTECTED] wrote in message
news:a2u3sa$q3e$[EMAIL PROTECTED]...
  Hi,
  I've got a question. Does anyone know how to set object in 2-factor
  dimensional space ...
  I heard that factor score for a product is equal to product of the
suitable
  factor loadings and variables mean. i.e.
  f(m,p)=a(1,m)u(1,p) +a(2,m)u(2,p)+ ...+a(j,m)u(j,p)
  where: f(m,d) - factor score for m-factor,  p-th - consumer product ,
u(*) -
  mean for variable j and product p.
  Could you tell me is this true? How to proof this formally




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Re: factor Analysis

[Huxley]

Uzytkownik Gottfried Helms [EMAIL PROTECTED] napisal w wiadomosci
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 It's not so simple. You have to do matrix-inversion for
 that.

Not simple? I heard that taking suitable factor loadings and every variable
mean I can obtain this space. e.g. (I do not know is it true)
Let mean for car1 and questions 10 (variables):
mean X1=1
mean X2=2
..
mean X10=10
I have 2 factor score.
factor loadins (aij) I have, therefore for first factor score, co-odrinate
for car1 is
F1(for car1)=1*a(1,1)+2*a(2,1)+3*a(3,1)+...+10*a(10,1)
is it true?

Huxley




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factor Analysis

[Huxley]

Hi,
I've got a question. Does anyone know how to set object in 2-factor
dimensional space i.e I have 2 factor score. Therefore I can put variables
in this space. But variables describe objects (i.e. these are 12 consumer
products) and I don't care variables in space but only these products.
I heard that factor score for a product is equal to product of the suitable
factor loadings and variables mean. i.e.
f(m,p)=a(1,m)u(1,p) +a(2,m)u(2,p)+ ...+a(j,m)u(j,p)
where: f(m,d) - factor score for m-factor,  p-th - consumer product , u(*) -
mean for variable j and product p.
Could you tell me is this true? How to proof this formally


Huxley




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