Since I am always excited about learning new things, I tried
viewsource xtsum.ado. Everything worked nicely, but I found the
following nine lines at the end of the ado-file and I am wondering why
they are there.
. sum cost avgcost dcost
Variable | Mean Std. Dev. Min Max | Observations
-----------------+--------------------------------------------+----------------
----+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
longlong overall | 123456789 123456789 3.154 191.56 | N =12345678
longlong overall | 44.44588 46.30909 3.154 191.56 | N =12345678
between | 44.57574 4.4645 125.584 | n = 22
within | 20.41346 123456789 912345678 | T-bar = 6
It is not a critical thing to know but I am just curious.
Regards,
seb
On 7/6/06, Nick Cox <n.j.cox@durham.ac.uk> wrote:
Quite so. Indeed, knowing that -xtsum- is implemented as an .ado file
(strictly, not a .do file) means that
viewsource xtsum.ado
will give you a view of the code, without (a) needing
to doing a -which- to find out precisely where the
file is, or (b) any risk of modifying the code.
This tip is explained in more detail in
SJ-6-1 pr0022 . . . . . . . . . . . Stata tip 30: May the source be with you
Q1/06 SJ 6(1):149--150 (no commands)
tip for using viewsource to locate and view source
code or text files
and in "Thirty-three Stata Tips" from StataCorp.
Nick
n.j.cox@durham.ac.uk
Neil Shephard
> On 7/6/06, Podestà, Federico <Federico.Podesta@amm.unitn.it> wrote:
>
> > I have (I think) a simple problem: I would like to know
> formulas used by the -xtsum- command to obtain the betweem
> standard deviation and the within standard deviation.
> > In particular I would like to know Stata code to compute
> such statistics by hand solving all parts of the formulas
> step by step.
>
> The formulas for the methods implemented in Stata (at least those I've
> ever had recourse to look up) are given in the manuals, in this
> instance it will be [XT].
>
> In this instance because -xtsum- is implemented as a do-file....
>
> . which xtsum
> /usr/local/stata9/ado/base/x/xtsum.ado
> *! version 1.0.9 06aug2004
>
> ..you can look at the code yourself by viewing the relevant file in a
> text-editor.
>
> (Be wary of modifying the file which will break things. If you want
> to make modifications, don't, instead clone the do-file to your
> personal-ado file and rename it, and make modifications to that).
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