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From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: RE: yscale in anovaplot |

Date |
Mon, 27 Apr 2009 10:55:11 +0100 |

That's a very helpful reference to keep questions clear and specific. That web page gives two graphs, and (modulo cosmetic details) both are obtainable directly via -anovaplot-. The only twist is that the -anova- to precede it is simpler than the -anova- used as example. use http://www.ats.ucla.edu/stat/stata/examples/kirk/spf2-4, clear anova y a b a*b anovaplot anovaplot, scatter(ms(none)) anovaplot b a anovaplot b a, scatter(ms(none)) The moral that the plots you want may pertain to a simpler ANOVA than that you fit is valuable, and I'll build this example into the next revision of the help for -anovaplot-. Nick n.j.cox@durham.ac.uk David Airey Typical plots in the context of a split plot design are here: http://www.ats.ucla.edu/stat/stata/examples/kirk/kirkstata12.htm On Apr 26, 2009, at 1:19 PM, David Airey wrote: > In the simplest within subject design, the paired ttest, it makes > sense to plot the data by subject, a line per subject. Or if you > measure subjects repeatedly over time, it also makes sense to keep > the graphic by subject. Or if you measure two groups, pre and post, > it makes sense to plot either two groups of different colored lines > (one line per subject) or ignore subject and make a profile plot as > other software does. As far as I can tell, none of the permutations > of the factors does this, and that is why I said anovaplot is for > between subjects designs only, or as the help says with maybe one > covariate. My query was as much to Diego, who seemed satisfied with > his use of -anovaplot- in a repeated measures context. I was just > curious what his final plot looked like and from what model. On Apr 26, 2009, at 12:14 PM, Nick Cox wrote: >> You use it the way you expect to be most fruitful. >> >> I'm not minded to go upstream and find out what the example is >> about, or >> learn enough about the subject-matter to make a guess at what >> should be >> most helpful. >> >> But the default -anovaplot- has no inbuilt intelligence. It's likely >> that some permutation of the factors improves on the default plot, >> for >> example >> >> anovaplot s a b >> >> A simple but important issue is that whenever identifiers are quite >> arbitrary, putting them on one axis may not yield a clear picture. It >> may be worth re-labelling identifiers to make structure clearer. David Airey >> I always use it for between subjects ANOVAs. Perfect for that. >> >> The key thing in my response is that _I_ have not been satisfied with >> my use in within subject designs or mixed models. >> >> Maybe I was not using it correctly. Let's use an example from UCLA >> ATS, so that I can get it as correctly intended. >> >> From >> >> http://www.ats.ucla.edu/stat/stata/faq/xtmixed.htm >> >> just focusing on the ANOVA aspects of the page, let's do: >> >> use http://www.ats.ucla.edu/stat/stata/examples/kirk/spf2-4, clear >> anova y a / s|a b a*b /, repeated(b) >> >> How do you use -anovaplot- here? On Apr 26, 2009, at 11:26 AM, Nick Cox wrote: >>> 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. 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 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.) >>>> 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 ? * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: RE: yscale in anovaplot***From:*David Airey <david.airey@vanderbilt.edu>

**References**:**st: re: first difference in multidimensional panel***From:*Kit Baum <baum@bc.edu>

**st: yscale in anovaplot***From:*Diego Bellavia <bellavia.diego@mac.com>

**st: RE: yscale in anovaplot***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**Re: st: RE: yscale in anovaplot***From:*David Airey <david.airey@vanderbilt.edu>

**RE: st: RE: yscale in anovaplot***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**Re: st: RE: yscale in anovaplot***From:*David Airey <david.airey@vanderbilt.edu>

**RE: st: RE: yscale in anovaplot***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**Re: st: RE: yscale in anovaplot***From:*David Airey <david.airey@vanderbilt.edu>

**Re: st: RE: yscale in anovaplot***From:*David Airey <david.airey@vanderbilt.edu>

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