[R] Summary vs fivenum results for Q3

[Ravi Varadhan]

Please read the relevant help pages:
?fivenum
?boxplot.stats

Hint: Length of your data vector is an "even" number.

Ravi.

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Ravi Varadhan, Ph.D.

Assistant Professor, The Center on Aging and Health

Division of Geriatric Medicine and Gerontology 

Johns Hopkins University

Ph: (410) 502-2619

Fax: (410) 614-9625

Email: rvaradhan at jhmi.edu

Webpage:  http://www.jhsph.edu/agingandhealth/People/Faculty/Varadhan.html

 

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-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
Behalf Of Schaefer, Robert L. Dr.
Sent: Tuesday, October 09, 2007 11:20 AM
To: r-help at stat.math.ethz.ch
Subject: [R] Summary vs fivenum results for Q3

I've just started using R and am still a neophyte, but I found the following
curious result.  I'm using the current version of R (2.5.1 (2007-06-27) ).

Why are the results for the third quartile different in the output from the
summary and fivenum commands?  For the following data set

457     514     530     530     538     560     687     745     745     778
786     790     792     821     821     822     822
828     845     850     886     886     886     913     1050    1050    1065
1065    1065    1065    1090    1130

Summary yields:

   Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
  457.0   745.0   822.0   825.4   947.2  1130.0

While fivenum yields:

[1]  457.0  745.0  822.0  981.5 1130.0

The third quartile is being correctly calculated in the fivenum command and
incorrectly in the summary command.

Bob

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Robert L. Schaefer, Professor of Statistics
Department of Mathematics and Statistics
Miami University
Oxford, Ohio 45056  (513) 529-3533 (513) 529-5818 (sec)
SchaefRL at MUOhio.Edu  HTTP://WWW.USERS.MUOHIO.EDU/SchaefRL
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++

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