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RE: st: RE: outreg/estimates type commands for ttest


From   Nishant Dass <nishant_dass@yahoo.com>
To   statalist@hsphsun2.harvard.edu
Subject   RE: st: RE: outreg/estimates type commands for ttest
Date   Thu, 24 Aug 2006 09:48:05 -0700 (PDT)

Wow!  I admire your effort in responding to the query in
such detail.  

Thanks for referring me to -help smcl-; I found "{space #}"
which worked well for adding space between the two numeric
columns.  (I see "{space #}" is also written into -dlist-.)

One last thing - could you please tell me where could I
read more about subcommands like "_skip", "_column",
"_char", etc. mentioned under -display-?

Thanks a lot!

Nishant


--- Nick Cox <n.j.cox@durham.ac.uk> wrote:

> The variable names displayed at left are of unequal
> length. 
> 
> In contrast I know that I would like the first column of
> numeric 
> results to be aligned vertically and to be a column in
> the strict 
> sense. Thus I specify "{col 22}", which is a SMCL
> directive. 
> See -help smcl-. 
> 
> SMCL is Stata's own mark-up language. The name is a
> contraction of 
> SMCL Makes Cooler Logs (the documentation is in error on
> this point). 
> 
> There is an alternative which would be to specify that
> the number of 
> spaces skipped depends on the length of the variable
> name, 
> but choosing a particular column is much easier. 
> 
> Also, in this case 22 is empirically chosen, as none of
> the variable names 
> in the auto dataset is especially long. For other
> datasets 
> I would need to use a column greater than 22, or to
> consider 
> abbreviating the variable name. 
> 
> In contrast, for the spacing between two columns of
> numeric results 
> my use of formats implies that each column (field) is of
> constant width, 
> so I know that I can just give so many spaces. In this
> case I do have 
> a simple alternative, which is to specify 
> columns for the start of each field using "{col #}", but
> that 
> would oblige me to do some arithmetic, which 
> seems too much like hard work. 
> 
> So the laziness of the programmer is paramount here,
> except that 
> it works. 
> 
> -dlist- from SSC is a moderately simple worked example
> showing 
> various similar tricks, including also abbreviations,
> trimmings 
> of leading and trailing spaces, display of variable
> labels 
> and display of value labels. 
> 
> Nick 
> n.j.cox@durham.ac.uk 
> 
> Nishant Dass
>  
> > Hi Nick,
> > 
> > I have a small question about the loop that you
> provided
> > below.  What does the "{col 22}" do?  I tried searching
> for
> > it but couldn't find any explanation; it seems that you
> are
> > providing the width of the column that contains `v'.  
> > 
> > If that is the case, then why can't we do the same for
> the
> > subsequent columns containing "r(t)" (instead of
> providing
> > some blank space with "    ")?  Is it because this
> second
> > column isn't in text format?
> > 
> > Sorry for the bother but a clarification would be
> helpful.
>  
> > --- Nick Cox <n.j.cox@durham.ac.uk> wrote:
> > 
> > > In the case of t tests, a work-around is obtained
> > > by noting that the results of 
> > > 
> > > regress <response> <binary variable>
> > > 
> > > are equivalent to 
> > > 
> > > ttest <response>, by(<binary variable>) 
> > > 
> > > so that -outreg- or -estout- (which I think 
> > > you mean here rather than -estimates-) can then be 
> > > used. 
> > > 
> > > Alternatively, a knit-it-yourself approach is 
> > > very simple: 
> > > 
> > > . foreach v of var price-gear {
> > >   2. qui ttest `v', by(foreign)
> > >   3. di as txt "`v'" "{col 22}" as res %6.3f  r(t) " 
>    
> > >    "  %5.4f  r(p)
> > >   4. }
> > > price                -0.414         0.6802
> > > mpg                  -3.631         0.0005
> > > rep78                -6.016         0.0000
> > > headroom              2.609         0.0110
> > > trunk                 3.268         0.0017
> > > weight                6.246         0.0000
> > > length                5.890         0.0000
> > > turn                  6.903         0.0000
> > > displacement          6.597         0.0000
> > > gear_ratio           -8.476         0.0000
> > > 
> > > The essentials: 
> > > 
> > > 0. Looping over a variable list. 
> > > 
> > > 1. -quietly- executing your statistical command. 
> > > 
> > > 2. Picking up r() stuff (or indeed e() stuff) left in
> > > memory. 
> > > You can -return list- or -ereturn list- or read the
> > > manual 
> > > entry. 
> > > 
> > > 3. -display-ing results, with some attention to
> layout
> > > and 
> > > formats. 
> > > 
> > > The example above is the third iteration of a real
> > > example. I 
> > > guessed lucky at r(p) and r(t) and then made changes
> to 
> > > the layout and formats. 
> > > 
> > > At this point you may want to transfer to your text
> or 
> > > word processor. 
> > > 
> > > Although I have mixed feelings about the program, 
> > > I note that -makematrix- from SSC gets you there 
> > > too:
> > > 
> > > . makematrix , from(r(p) r(t)) : ttest price-gear,
> > > by(foreign)
> > > 
> > >                        p           t
> > >        price   .88738723   .14215113
> > >          mpg   .00008982  -4.1688344
> > >        rep78   8.313e-08  -6.0162381
> > >     headroom   .00494105   2.9071556
> > >        trunk   .00055112   3.6288312
> > >       weight   2.047e-09   6.9268345
> > >       length   2.461e-08   6.3182882
> > >         turn   1.721e-10   7.5259982
> > > displacement   3.629e-09   6.7875143
> > >   gear_ratio   1.590e-12  -8.6552193
> > > 
> > > . makematrix results , from(r(p) r(t)) format(%6.3f)
> :
> > > ttest price-gear, by(foreign)
> > > 
> > > results[10,2]
> > >                    p       t
> > >        price   0.887   0.142
> > >          mpg   0.000  -4.169
> > >        rep78   0.000  -6.016
> > >     headroom   0.005   2.907
> > >        trunk   0.001   3.629
> > >       weight   0.000   6.927
> > >       length   0.000   6.318
> > >         turn   0.000   7.526
> > > displacement   0.000   6.788
> > >   gear_ratio   0.000  -8.655
> > > 
> > > In this case, it is fortunate that 3 d.p. work fairly
> > > well for both p and 
> > > t values. But then with most statistical results 3
> d.p.
> > > often work well, 
> > > although we frequently show many more places as a
> matter
> > > of social ritual. 
> > > 
> > > Nick 
> > > n.j.cox@durham.ac.uk 
> > > 
> > > Nishant Dass
> > >  
> > > > Is anyone aware of a command (like "outreg" or
> > > "estimates")
> > > > that I could use to tabulate "ttest" or "median"
> test
> > > > results?
> 
> *
> *   For searches and help try:
> *   http://www.stata.com/support/faqs/res/findit.html
> 
=== message truncated ===


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