Bug 130910 - Error in the QUARTILE function of CALC ?
Summary: Error in the QUARTILE function of CALC ?
Status: CLOSED NOTABUG
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Calc (show other bugs)
Version:
(earliest affected)
6.4.0.3 release
Hardware: All Windows (All)
: medium normal
Assignee: Not Assigned
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-02-24 19:25 UTC by Rüdiger Bamberg
Modified: 2020-02-24 20:28 UTC (History)
2 users (show)

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Description Rüdiger Bamberg 2020-02-24 19:25:27 UTC
Description:
I think, there is an error in the function QUARTILE of the CALC-section

For example: 
Dataset: 5 6 9 12 17 20 22 22 19 14 9 6

QUARTILE (..;0) is correct 5 (= MIN),
QUARTILE (..;1) delivers 8.25 (???) (should be 7.5),
QUARTILE (..,2) is correct 13 (= MEDIAN),
QUARTILE (..;3) delivers 19.25 ??? (should be 19.5),
QUARTILE (..,4) is correct 22 (= MAX).


LO Version: 6.4.0.3 (x64)
Build-ID: b0a288ab3d2d4774cb44b62f04d5d28733ac6df8

Actual Results:
As described above

Expected Results:
As described above


Reproducible: Always


User Profile Reset: No



Additional Info:
As described above
Comment 1 himajin100000 2020-02-24 20:07:52 UTC
https://www.icalcu.com/stat/fivenum.html

[Tukey's hinge method] Minimum=5, Q1=7.5, Median=13, Q3=19.5, Maximum=22

[TI-83 & TI-84 & TI-89 method] Minimum=5, Q1=7.5, Median=13, Q3=19.5, Maximum=22

[Percentile method] Minimum=5, Q1=8.25, Median=13, Q3=19.25, Maximum=22
Comment 2 himajin100000 2020-02-24 20:13:10 UTC
At least, Excel 365 installed locally returns same value as calc.
Proposing NOTABUG
Comment 3 Eike Rathke 2020-02-24 20:28:34 UTC
Calc implements the percentile method, as common for all spreadsheet software. See the definition given in
https://docs.oasis-open.org/office/v1.2/os/OpenDocument-v1.2-os-part2.html#QUARTILE
and for a possible algorithm
https://docs.oasis-open.org/office/v1.2/os/OpenDocument-v1.2-os-part2.html#PERCENTILE