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From |
David Airey <david.airey@vanderbilt.edu> |

To |
statalist@hsphsun2.harvard.edu |

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

Date |
Mon, 27 Apr 2009 07:04:13 -0500 |

.

-Dave 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 areobtainable 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 quitearbitrary, putting them on one axis may not yield a clear picture.Itmay be worth re-labelling identifiers to make structure clearer.David AireyI always use it for between subjects ANOVAs. Perfect for that.The key thing in my response is that _I_ have not been satisfiedwithmy 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.Whatdo you do instead?A while back I went carefully through various classic texts onANOVAfrom the 1950s. As I recall none of them included any plots basedondata.David AireyI 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 2004On 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 reducetherange 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/

* * 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:*"Nick Cox" <n.j.cox@durham.ac.uk>

**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>

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