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From | "Nick Cox" <n.j.cox@durham.ac.uk> |
To | <statalist@hsphsun2.harvard.edu> |
Subject | RE: st: Several quantile plots in one diagram |
Date | Wed, 21 Apr 2010 13:52:49 +0100 |
Barbro is talking about -quantil2-, later renamed -qplot, written by myself. The searchable documentation makes the line of succession clear, so I do not know why there is any uncertainty on this point. . search quantil2 Keyword search Keywords: quantil2 Search: (1) Official help files, FAQs, Examples, SJs, and STBs Search of official help files, FAQs, Examples, SJs, and STBs SJ-6-4 gr42_4 . . . . . . . . . . . . . . . . . . Software update for qplot (help qplot if installed) . . . . . . . . . . . . . . . . . N. J. Cox Q4/06 SJ 6(4):597 better handling of x-axis titling, a new option allowing the user to specify an alternative plotting position or rank variable SJ-5-3 gr42_3 . . . . . . . . . . . . . . . . . . Software update for qplot (help qplot if installed) . . . . . . . . . . . . . . . . . N. J. Cox Q3/05 SJ 5(3):471 simplified syntax; both by() and over() are now allowed SJ-4-1 gr42_2 Software update for Quantile plots, generalized; renamed qplot (help qplot if installed) . . . . . . . . . . . . . . . . . N. J. Cox Q1/04 SJ 4(1):97 software update for quantil2, now renamed qplot STB-61 gr42.1 . . . . . . . Quantile plots, generalized: update to Stata 7.0 (help quantil2 if installed) . . . . . . . . . . . . . . . N. J. Cox 5/01 pp.10--11; STB Reprints Vol 10, pp.55--56 updated for use with Stata 7 STB-51 gr42 . . . . . . . . . . . . . . . . . . Quantile plots, generalized (help quantil2 if installed) . . . . . . . . . . . . . . . N. J. Cox 9/99 pp.16--18; STB Reprints Vol 9, pp.113--116 generalizes the quantile command by allowing more than one variable (or a by() option), more graphical choices, general plotting positions, and an option to reverse the order -quantil2- is indeed "pretty old". What's not explicit in this thread is that it produces the old graphics, for Stata 7 or less. It doesn't crash my more modern versions of Stata. -qplot- has been available since 2004, however. I don't understand how Barbro can install -quantil2- but not -qplot-, but no matter. I'll email her copies of the -qplot- files. Maarten is right: you _can_ do this yourself. For related advice in the same spirit, see SJ-7-2 gr0027 . . Stata tip 47: Quantile-quantile plots without programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox Q2/07 SJ 7(2):275--279 (no commands) tip on producing various quantile-quantile (Q-Q) plots I disagree with Martin about recommending official -quantile- here. -quantile- can only very awkwardly handle two or more groups; you might as do it all yourself. Nick n.j.cox@durham.ac.uk Widerstedt Barbro Thank you, that worked very well, but does this mean that the lazy-girl, no-think option is not available then :) ? Maarten buis --- On Wed, 21/4/10, Widerstedt Barbro wrote: > I have a panel dataset with 6 years, and I would like to > plot the distribution of a variable in a quantile plot > for each year in this panel. I have installed quantil2, > which causes Stata to shut down when I try to save the > graph. There seems to be upgrades (quantil2 is pretty > old), but because of firewall restrictions on the remote > workstation where Stata resides, I can't search or > install from STATA. I can't find the update qplot or > other updrage mentioned in e.g. Stata Journal > 2006(4) on SSC. Where can I find this functionality? > (I use Stata 10) You can always recreate the graph from first principle. In the example below I assume you want to display these distribution in the same plot. This plot is basically just a scatter plot. All you need to do is create the so called "plotting positions", that is, the values on the x-axis. This is discussed in this Stata FAQ: <http://www.stata.com/support/faqs/stat/pcrank.html> In the example below the rep78 variable takes the place of your year variable. *-------------- begin example --------------------- sysuse auto, clear recode rep78 1/2=3 // create plotting positions gen byte mis = missing(price,rep78) bys rep78 mis (price) : gen int i = _n if mis == 0 bys rep78 mis : gen int n = _N if mis == 0 gen hazen = (i - .5) / n twoway scatter price hazen if rep78 ==3 || /// scatter price hazen if rep78 ==4 || /// scatter price hazen if rep78 ==5, /// legend(order(1 "Average" /// "or worse" /// 2 "Good" /// 3 "Excellent" )) /// xtitle("fraction of the data") /// ytitle("quantiles of price") *--------------- end example ------------------------ (For more on examples I sent to the Statalist see: http://www.maartenbuis.nl/example_faq ) * * 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/