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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 13:45:40 +0100 |

Thanks for this. On your last point, I hope not; you should continue to regard -stripplot- as a bigger deal than -anovaplot-. Nick n.j.cox@durham.ac.uk David Airey Wow. And to think I have been using methods on that page rather than - anovaplot-? What a dummy. Tsk. Awesome and thanks Nick! Now maybe -anovaplot- will rival your - stripplot- as my favorite graphic command. On Apr 27, 2009, at 4:55 AM, Nick Cox wrote: > 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/

**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>

**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>

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