You can get anything you want, at Alice's Restaurant:
> quantile(d,.75,type=1)
75%
913
> quantile(d,.75,type=2)
75%
981.5
> quantile(d,.75,type=3)
75%
913
> quantile(d,.75,type=4)
75%
913
> quantile(d,.75,type=5)
75%
981.5
> quantile(d,.75,type=6)
75%
1015.75
> quantile(d,.75,type=7)
75%
947.25
> quantile(d,.75,type=8)
75%
992.9167
> quantile(d,.75,type=9)
75%
990.0625
"correctly calculated" has a sort of pre-post-modern flavor here...
url: www.econ.uiuc.edu/~roger Roger Koenker
email rkoenker at uiuc.edu Department of Economics
vox: 217-333-4558 University of Illinois
fax: 217-244-6678 Champaign, IL 61820
>
> On Oct 9, 2007, at 10:20 AM, Schaefer, Robert L. Dr. wrote:
>
>> 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
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-
>> guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>