Stata The Stata listserver
[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

Re: st: urgent help on pca


From   n j cox <n.j.cox@durham.ac.uk>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: urgent help on pca
Date   Tue, 31 May 2005 14:11:58 +0100

I cannot underststand all this. It seems that
you downloaded Jeroen Weesie's -pca- program and
got some results, but do not believe them and now want
for some reason to reinstall it. I predict that if you
reinstall this program you will get the same
results as previously.

There are no restrictions on the availability
of Jeroen's -pca-. Also, if you installed
it once, the same method should work again,
and there should be no need for private
help.

If you referring to official Stata's -pca-,
then it will not work with Stata 7, quite
apart from ethical considerations.

In any case, with Stata 7 principal components
analysis, classical sense, is if I remember
correctly obtainable with -factor, pc-. Do
not invoke the -factor()- option.

Incidentally, it is my experience both
on Statalist and elsewhere that expressing
"urgency" is usually counter-productive. The
number of people likely to jump to it just
because you think you deserve an especially quick reply
is typically exceeded by those more likely to
delete your posting on precisely those grounds.

Nick
n.j.cox@durham.ac.uk

Alice(Libo) Sun wrote

> I need a quick favor.

> I need to compute principal component analysis. My stata version is > > 7.0 and I do not have command 'pca'.

> I downloaded pca.ado from
> http://ideas.repec.org/c/boc/bocode/sjw33.html. I
> tried 'pca x1 x2 x3 x4 x5 x6 '.

> However, the results on Eigenvalue are different from that using
> 'factor x1 x2 x3 x4 x5 x6, factors(1) pcf'.

> Is factor command did what I want to do, that is, get the first
> component?

> I am not sure about the downloaded pca.ado. I am wondering if I could > get pca.ado and pca.hlp from someone privately?
> I won't distribute to others.


*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/




© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index