Thanks. That settles it. CS.
On Wed, 1 Apr 2009, Martin Weiss wrote:
:<>
:
:That is a rounding error b/c you transferred the mean and sd by hand....
:
:****
:clear*
:set obs 10000
:g x =rnormal()
:su x
:g x1=(x-r(mean))/r(sd)
:egen x2=std(x)
:su x?
:*****
:
:In the example, both results match...
:
:
:HTH
:Martin _______________________
:----- Original Message ----- From: "Caleb Southworth" <[email protected]>
:To: <[email protected]>
:Sent: Wednesday, April 01, 2009 10:05 PM
:Subject: st: what does -egen std- do?
:
:
:> How is the variable generated by -egen std- standardized?
:>
:> Here I take a variable, subtract the mean and divided by sd
:>
:> gen std_man=(P_math-45.20336)/13.3137
:>
:> Here's the egen version
:>
:> egen std_egn=std(P_math)
:>
:> . sum std*
:>
:> Variable | Obs Mean Std. Dev. Min Max
:> -------------+--------------------------------------------------------
:> std_man | 775 2.58e-07 .9999999 -3.019699 3.06426
:> std_egn | 775 -1.24e-09 1 -3.019699 3.06426
:>
:> What explains the difference in means?
:>
:> Caleb Southworth
:> Associate Professor
:> Univ. of Oregon Sociology
:> *
:> * For searches and help try:
:> * http://www.stata.com/help.cgi?search
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:> * http://www.ats.ucla.edu/stat/stata/
:>
:*
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:
Caleb Southworth
Associate Professor
Univ. of Oregon Sociology
*
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* http://www.ats.ucla.edu/stat/stata/
