stat: Quartile methods
09-08-2015, 04:07 PM
Post: #1
 hpfx Junior Member Posts: 28 Joined: Jan 2015
stat: Quartile methods
Hi,
as seen in wikipedia Quartile there are 3 methods to compute quartile.
bad luck, it's not the same for each national educational system...

Calculator like TI-83 (with lastest OS 5.1) allow you to choose a method.
but HP Prime only show one...

It would be nice for hpprime students to get Quartile as same as national system expect for each country.
If someone at hp company can think about that...
Thank you.
09-08-2015, 07:43 PM
Post: #2
 debrouxl Member Posts: 258 Joined: Dec 2013
RE: stat: Quartile methods
+1 on that feature request.
Post: #3
 Adriweb Junior Member Posts: 32 Joined: Jun 2014
RE: stat: Quartile methods
Indeed ; the TI-83 Premium CE just got this feature with OS 5.1, like you say, just a few days ago.
It looks like this:

(The labels could be better, like FR / US, but oh well, at least it's there )

09-09-2015, 12:44 PM
Post: #4
 ThomasA Junior Member Posts: 27 Joined: May 2014
RE: stat: Quartile methods
1+ on that request, too.
09-09-2015, 02:09 PM
Post: #5
 Gerald H Senior Member Posts: 1,627 Joined: May 2014
RE: stat: Quartile methods
Can anyone name some systems using methods 2 or 3?
09-09-2015, 02:13 PM
Post: #6
 salvomic Senior Member Posts: 1,396 Joined: Jan 2015
RE: stat: Quartile methods
(09-09-2015 02:09 PM)Gerald H Wrote:  Can anyone name some systems using methods 2 or 3?

I'm curious too, please, explain us with some examples...

∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C - DM42, DM41X - WP34s Prime Soft. Lib
09-10-2015, 05:26 AM
Post: #7
 cyrille de brébisson Senior Member Posts: 1,047 Joined: Dec 2013
RE: stat: Quartile methods
Hello,

Some mathematics definition are 'culture dependent'.
For example a triangle is defined in Latin country as polygon formed of 3 points. In Anglo Saxon countries as a polygon formed by 3 non-aligned points. It makes a difference.

It is the same for Quartiles.
To find quartiles, you have to first find the middle of an ordered list.
BUT how do you defined the middle of an odd sized list? multiple answers, multiple systems.
Then, you have to find the middle of the 2 sides. Well, what do you do with the middle that you already found? Do you include it in the sides or not? multiple answers, multiple definitions of Quartiles...

At this point, Prime supports the Anglo Saxon definition of Quartiles only.

Cyrille
09-10-2015, 06:21 AM (This post was last modified: 09-10-2015 06:26 AM by StephenG1CMZ.)
Post: #8
 StephenG1CMZ Senior Member Posts: 1,036 Joined: May 2015
RE: stat: Quartile methods
My maths class was a long time ago, so maybe I am remembering wrongly. But I seem to recall that which definition you should use for the middle of an odd-sized list depended not on culture (which we were not aware of pre-Internet), but on application. For some applications like shoe sizes you might choose one of the two middle values. For other applications you might average them.

In the past when calculators only handled numbers it was only possible to return a numeric value - and whichever number you choose is always going to confuse someone with a different assumption or mode setting.

I would propose that the least confusing value to return on a modern calculator is not some random number depending on some probably unspecified mode setting hidden in one menu or another depending on which calculator you have. The best value to return is a list containing the two numbers of interest. A list containing two middle numbers for odd-sized lists (and for consistency a list containing one number for an even sized list).

That way there are no unexplained mode settings and no pupils getting different answers!

Once you have that list of one or two numbers visible to the pupil, the pupil can decide whether to use one or the other, or choose one at random, or calculate the average. All simple clear and explainable maths depending on the application. No hidden mode settings necessary.

Stephen Lewkowicz (G1CMZ)
https://my.numworks.com/python/steveg1cmz
09-11-2015, 05:14 AM
Post: #9
 cyrille de brébisson Senior Member Posts: 1,047 Joined: Dec 2013
RE: stat: Quartile methods
cool,

here is a fourth method :-)

cyrille
09-11-2015, 05:41 AM
Post: #10
 Gerald H Senior Member Posts: 1,627 Joined: May 2014
RE: stat: Quartile methods
(09-11-2015 05:14 AM)cyrille de brébisson Wrote:  cool,

here is a fourth method :-)

cyrille

Where?

Excel uses method 2 from the Wikipedia article, no alternative & no detailed explanation.
09-11-2015, 06:16 AM
Post: #11
 DrD Senior Member Posts: 1,133 Joined: Feb 2014
RE: stat: Quartile methods
The G1CMZ proposal...

excel, another calculator, another method. Cyrille's point.
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