From: Berton Gunter <gunter.berton_at_gene.com>

Date: Fri 02 Dec 2005 - 05:53:18 EST

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Dec 02 06:22:55 2005

Date: Fri 02 Dec 2005 - 05:53:18 EST

It's already there in EDA! Se pp 39-47.

- Bert Gunter Genentech Non-Clinical Statistics South San Francisco, CA

"The business of the statistician is to catalyze the scientific learning process." - George E. P. Box

> -----Original Message-----

*> From: r-help-bounces@stat.math.ethz.ch
**> [mailto:r-help-bounces@stat.math.ethz.ch] On Behalf Of
**> Michael H. Prager
**> Sent: Thursday, December 01, 2005 10:11 AM
**> To: r-help@stat.math.ethz.ch
**> Subject: Re: [R] Impaired boxplot functionality - mean
**> instead of median
**>
**> All--
**>
**> Would someone kindly post the reference to Tukey's formula
**> for a boxplot
**> without whiskers?
**>
**> I am looking at his book "Exploratory Data Analysis" from 1977. The
**> index includes "box-and-whisker" plot but not "boxplot." On
**> page 39-40
**> construction of the plot is described, including the statements: "We
**> draw a long, thinnish box that stretches from hinge to hinge,
**> crossing
**> it with a bar at the median. Then we draw a 'whisker' from
**> each end of
**> the box to the corresponding extreme."
**>
**> MHP
**>
**>
**> on 12/1/2005 11:57 AM P Ehlers said the following:
**>
**> >I'd like to add two comments to Martin's sensible response.
**> >
**> >1. I've seen several intro-stats textbooks that define a
**> >boxplot to have whiskers to the extreme data values
**> >and then define Tukey's boxplot as a "modified" boxplot.
**> >I wish authors wouldn't do that.
**> >
**> >2. I've also seen boxplots used for sample sizes as small
**> >as -- are you ready for it? -- n = 2!! (Admittedly, only in
**> >plots comparing several groups.) The help page for
**> >stripchart() points out that stripcharts "are a good
**> >alternative to boxplots when sample sizes are small".
**> >My own rule-of-thumb: n > 20 for single boxplots, n > 12
**> >for multiple boxplots.
**> >
**> >Peter Ehlers
**> >
**> >Martin Maechler wrote:
**> >
**> >
**> >
**> >>Boxplots were invented by John W. Tukey and I think should be
**> >>counted among the top "small but smart" achievements from the
**> >>20th century. Very wisely he did *not* use mean and
**> standard deviations.
**> >>
**> >>Even though it's possible to draw boxplots that are not boxplots
**> >>(and people only recently explained how to do this with R on this
**> >> mailing list), I'm arguing very strongly against this.
**> >>
**> >>If I see a boxplot - I'd want it to be a boxplot and not have
**> >>the silly (please excuse) 10%--------90% whiskers which
**> >>declare 20% of the points as outliers {in the boxplot sense}.
**> >>
**> >>If you want the mean +/- sd plot, do *not* misuse boxplots
**> >>for them, please!
**> >>
**> >>Martin Maechler, ETH Zurich
**> >>
**> >>
**> >>
**> >>
**> >>>>>>>"Evgeniy" == Evgeniy Kachalin <ka4alin@yandex.ru>
**> >>>>>>> on Thu, 01 Dec 2005 19:04:47 +0300 writes:
**> >>>>>>>
**> >>>>>>>
**> >> Evgeniy> Hello to all users and wizards.
**> >> Evgeniy> I am regulary using 'boxplot' function or its
**> analogue - 'bwplot' from
**> >> Evgeniy> the 'lattice' library.
**> >>
**> >> [there's the lattice *package* !]
**> >>
**> >> Evgeniy> But they are, as far as I understand, totally
**> >> Evgeniy> flawed in functionality: they miss ability to
**> select what they would
**> >> Evgeniy> draw 'in the middle' - median, mean. What the
**> box means - standard
**> >> Evgeniy> error, 90% or something else. What the
**> whiskers mean - 100%, 99% or
**> >> Evgeniy> something else.
**> >> Evgeniy> Is there any way to realize it? Or is there
**> any other good data
**> >> Evgeniy> visualization function for comparing means of
**> various data groups?
**> >> Evgeniy> Ideally I would like to have a bit more
**> customised function for doing
**> >> Evgeniy> that. For example, 'boxplot(a~b,data=d,mid='mean').
**> >>
**> >>
**> >> Evgeniy> --
**> >> Evgeniy> Evgeniy, ICQ 38317310.
**> >>
**> >>______________________________________________
**> >>R-help@stat.math.ethz.ch mailing list
**> >>https://stat.ethz.ch/mailman/listinfo/r-help
**> >>PLEASE do read the posting guide!
**> http://www.R-project.org/posting-guide.html
**> >>
**> >>
**> >
**> >______________________________________________
**> >R-help@stat.math.ethz.ch mailing list
**> >https://stat.ethz.ch/mailman/listinfo/r-help
**> >PLEASE do read the posting guide!
**> http://www.R-project.org/posting-guide.html
**> >
**> >
**>
**> --
**>
**> Michael Prager, Ph.D.
**> Population Dynamics Team, NMFS SE Fisheries Science Center
**> NOAA Center for Coastal Fisheries and Habitat Research
**> Beaufort, North Carolina 28516
**> http://shrimp.ccfhrb.noaa.gov/~mprager/
**> Opinions expressed are personal, not official. No
**> government endorsement of any product is made or implied.
**>
**> ______________________________________________
**> R-help@stat.math.ethz.ch mailing list
**> https://stat.ethz.ch/mailman/listinfo/r-help
**> PLEASE do read the posting guide!
**> http://www.R-project.org/posting-guide.html
*

>

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Dec 02 06:22:55 2005

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