Hello,
What I meant is that this time, the result is "correct".
Both formula produce the same results.
Thanks.
Jitian
----- Original Message -----
From: "Richard Williams" <[email protected]>
To: <[email protected]>
Sent: Friday, April 09, 2004 10:08 PM
Subject: Re: st: Inconsistent Result of generating variables
> At 09:22 PM 4/9/2004 -0400, Jitian Sheu wrote:
> >Hello, Thank you very much.
> >Based on your explaination, I try to use: (`b21')^2 instead of using
> >`b21'^2.
> >Stata creates the same results.
>
> I hope you mean you got the same results as I did, not the same incorrect
> results you got earlier! Anyway, here is the Stata FAQ I was thinking
of -
> "I coded 'a'2 and got the wrong sign. Why?" See
>
> http://www.stata.com/support/faqs/lang/macpow.html
>
> The trick is that when you say,
>
> local b21=-0.25
>
> You naturally assume that Stata will think `b21' means "negative
> .25". But, Stata actually interprets it as "minus .25". Hence, with
> `b21'^2, exponentiation gets done first and then subtraction, leaving you
> with -.0625 rather than +.0625.
>
> The FAQ suggests two workarounds:
>
> * Use scalars instead of local macros, e.g.
>
> scalar b21 = -.25
>
> * Or, bind the macro in parentheses when taking powers, e.g
>
> (`b21')^2
>
> *
> * 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/
>
*
* 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/
