Dear colleagues,
I think it would be a good idea to include a short note in the R
boxplot() help file, stating exactly how the confidence levels are
calculated
(the notches are +/- 1.58 IQR/sqrt(n)) - at least as a guidance for
users not advanced enough to directly interpret the code.
Would
On Mon, 1 Mar 2004, David James wrote:
Prof Brian Ripley wrote:
On Mon, 1 Mar 2004, Martin Maechler wrote:
TL == Thomas Lumley [EMAIL PROTECTED]
on Mon, 1 Mar 2004 09:54:48 -0800 (PST) writes:
TL On Mon, 1 Mar 2004, Christoph Scherber wrote:
Dear list members,
On 1 Mar 2004 at 9:54, Thomas Lumley wrote:
On Mon, 1 Mar 2004, Christoph Scherber wrote:
Dear list members,
Can anyone tell me how the notches in boxplot(Y~X,notch=T) are
calculated? What do these notches represent exactly? I´d suppose
they are Conficence Intervals for the median,
I think John Tukey's idea was that this formula (or just the fact of
using median and quartiles) is still often approximately correct
for quite a few kinds of moderate contaminations...
It may be approximately correct for the width of a CI (and when I checked
it was only appproximately
In McGill et al. (1978) there´s a description of the calculation as
follows (p. 16):
The widths [are] computed from the midspread or interquartile range (R)
of the data (...), and the number of observations (N) for each group.
The Gaussian-based asymptotic approximation (Kendall and Stuart
A Google search showed that all this was discussed in April 1988 with
an extensive reply to the question from M Maechler.
I, as a non-statistician, blindly believed what was written in the
boxplot() help file, I am sure many would be grateful to this help
being modified.
I still do not
On Tue, 2 Mar 2004, P. B. Pynsent wrote:
A Google search showed that all this was discussed in April 1988 with
an extensive reply to the question from M Maechler.
I, as a non-statistician, blindly believed what was written in the
boxplot() help file, I am sure many would be grateful to this
A Google search showed that all this was discussed in April 1988 with
an extensive reply to the question from M Maechler.
Sorry above should be 1998
On 2 Mar 2004, at 10:18, Christoph Scherber wrote:
Dear colleagues,
I think it would be a good idea to include a short note in the R
boxplot()
On Tue, 2 Mar 2004, Michael Friendly wrote:
I think John Tukey's idea was that this formula (or just the fact of
using median and quartiles) is still often approximately correct
for quite a few kinds of moderate contaminations...
It may be approximately correct for the width
P == P B Pynsent [EMAIL PROTECTED]
on Tue, 2 Mar 2004 15:16:23 + writes:
P A Google search showed that all this was discussed in April 1998 with
P an extensive reply to the question from M Maechler.
Yes, indeed:
http://finzi.psych.upenn.edu/R/Rhelpold/archive/0839.html ,
On Tue, 2 Mar 2004 07:24:41 -0800 (PST)
Thomas Lumley [EMAIL PROTECTED] wrote:
On Tue, 2 Mar 2004, P. B. Pynsent wrote:
A Google search showed that all this was discussed in April 1988 with
an extensive reply to the question from M Maechler.
I, as a non-statistician, blindly believed
Dear list members,
Can anyone tell me how the notches in boxplot(Y~X,notch=T) are
calculated? What do these notches represent exactly? I´d suppose they
are Conficence Intervals for the median, but I´ve also been told they
might show Least Significant Difference (LSD) equivalents.
I would
On Mon, 1 Mar 2004, Christoph Scherber wrote:
Dear list members,
Can anyone tell me how the notches in boxplot(Y~X,notch=T) are
calculated? What do these notches represent exactly? I´d suppose they
are Conficence Intervals for the median, but I´ve also been told they
might show Least
TL == Thomas Lumley [EMAIL PROTECTED]
on Mon, 1 Mar 2004 09:54:48 -0800 (PST) writes:
TL On Mon, 1 Mar 2004, Christoph Scherber wrote:
Dear list members,
Can anyone tell me how the notches in boxplot(Y~X,notch=T) are
calculated? What do these notches represent
On Mon, 1 Mar 2004, Martin Maechler wrote:
TL == Thomas Lumley [EMAIL PROTECTED]
on Mon, 1 Mar 2004 09:54:48 -0800 (PST) writes:
TL On Mon, 1 Mar 2004, Christoph Scherber wrote:
Dear list members,
Can anyone tell me how the notches in boxplot(Y~X,notch=T) are
Prof Brian Ripley wrote:
On Mon, 1 Mar 2004, Martin Maechler wrote:
TL == Thomas Lumley [EMAIL PROTECTED]
on Mon, 1 Mar 2004 09:54:48 -0800 (PST) writes:
TL On Mon, 1 Mar 2004, Christoph Scherber wrote:
Dear list members,
Can anyone tell me how the
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