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RE: st: RE: yscale in anovaplot


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: RE: yscale in anovaplot
Date   Sun, 26 Apr 2009 17:26:22 +0100

2.1.1 is the latest publicly available version. 

-anovaplot- plots observed and fitted values after -anova- in terms of
predictor levels. 

It's a bit surprising to hear that you never found that useful. What do
you do instead? 

A while back I went carefully through various classic texts on ANOVA
from the 1950s. As I recall none of them included any plots based on
data. 

Nick 
n.j.cox@durham.ac.uk 

David Airey

I never found -anovaplot- useful for anything but between subject  
designs. I'd be curious to see the repeated measures plots using - 
anovaplot-.

Is the version on SSC not the latest?

I have

. which anovaplot
/Users/dairey/Library/Application Support/Stata/ado/plus/a/anovaplot.ado
*! 2.1.1 NJC 6 November 2004

-Dave

On Apr 26, 2009, at 10:52 AM, Nick Cox wrote:

> Thanks to Diego for this interesting question and to Thomas for
> answering it so fully.
>
> To fill in a gap and to fill out the implicitly needed discussion:
>
> -anovaplot- is a program in the -modeldiag- package written up in the
> Stata Journal within
>
> SJ-4-4  gr0009  . . . . . . . . . . Speaking Stata: Graphing model
> diagnostics
>        . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  N.
> J. Cox
>        (help anovaplot, indexplot, modeldiag, ofrtplot, ovfplot,
>        qfrplot, racplot, rdplot, regplot, rhetplot, rvfplot2,
>        rvlrplot, rvpplot2 if installed)
>        Q4/04   SJ 4(4):449--475
>        plotting diagnostic information calculated from residuals
>        and fitted values from regression models with continuous
>        responses
>
> There's also an equivalent package on SSC that includes older versions
> of these programs.
>
> The paper is accessible to all via
>
> http://www.stata-journal.com/sjpdf.html?articlenum=gr0009
>
> -anovaplot- is described on p.458. I add this comment, which is  
> relevant
> to Diego's question:
>
> "It is curious that analysis-of-variance people typically draw
> interaction plots but suppress the data, whereas regression people
> prefer to draw scatterplots showing both observed and fitted values.
> Admittedly, a complicated set of crossing lines showing interactions  
> may
> seem to leave little scope for showing data effectively, while a
> relatively
> simple regression leaves plenty of scope, but the difference is
> nevertheless intriguing."
>
> I still treasure a comment made by a senior Stata user, who might not
> want to be named for this, to the effect that showing the data on the
> graph typically confuses the issue.
>
> Nevertheless I'll think about adding a -nodata- option, possibly  
> with a
> sting in the tail. (For example, it might -drop- all your data, or  
> some
> such.)
>
> Nick
> n.j.cox@durham.ac.uk
>
> Thomas Steichen
> ===============
>
> Although you have suppressed printing a symbol for the data points via
> -scatter(msym(none))-, Stata still allows room for that invisible data
> in its y-axis range. Therefore you cannot reduce the range given the  
> way
> the code is written. Editing the code to allow what you want is pretty
> straightforward.
>
> Change line:
>                numlist "2/`= 1 + `: word count `fits'''"
> To:
>                numlist "1/`= 1 + `: word count `fits'''"
>
> And line:
>            twoway scatter `y' `x1' if e(sample), `scatter' ///
> To:
>            twoway `scatter'  ///
>
> Then edit line:
> program anovaplot, sort
> To:
> program anovaplot0, sort
>
> Save it with new name anovaplot0.ado and invoke it with command
> -anovaplot0-
>
> Nick Cox's original will keep working and you'll have this one for  
> your
> purpose.
>
> Of course, you could get fancy and add a -nodata- option that allows
> both forms in a single program.
>
> Diego Bellavia
> ==============
>
> I am trying to plot an ANOVA for repeated measures model using the
> amazing anovaplot command.
> Everything works fine except the yscale range. I need to reduce the
> range and increase the scale
> to make differences clear. So I tried:
>
> anovaplot level groups, scatter(msym(none)) yscale (range(-12 -24))
> ylabel(-12 (2) -24)
>
> The problem is that I actually reduced the numbered range and the
> labelling but now almost half of the graph
> is empty. Is there any way to change the range so that I can take
> advantage of all the graph extension ?

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