I think this is just the programmer's (programmers') concrete
example of -summarize- output so they can keep track of
output layout. It is not part of the code concerned. Keeping
odd stuff like this at the end of a program file can beat keeping
notes on bits of {scrap|scratch} paper or in other files that
you can mislay or forget about. Other programmers document
special tricks, pious intentions, etc. in such places.
Nick
[email protected]
Sebastian F. B�chte
> 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.
> On 7/6/06, Nick Cox <[email protected]> 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
> > [email protected]
> >
> > Neil Shephard
> >
> > > On 7/6/06, Podest�, Federico
> <[email protected]> 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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