Re: set notation
- From: Calvin <crice5@xxxxxxxxxxxxxx>
- Date: Sat, 06 Oct 2007 21:24:16 -0700
We need a definition of set that allows multiple
identical elements. Here is a simple example.
A teacher might want to know how his students did
on a test given two years in a row. He just wants
to know the average score for each of the two
classes, so he doesn't need to know to whom each
score applies.
The first 'set' might then be {75,86,99,100,100,75}.
The second 'set' might be {80,70,95,95,90}.
He averages the the scores in each 'set', and thus
compares the two classes.
But the definition of set doesn't allow this, because
the first set would have to be {75,86,99,100}, and
the second set would have to be {80,70,95,90}, leading
to erroneous averaging of the scores.
Of course the teacher can get proper results without
obeying the definition of set, but that's not my
point. My point is that the universe does contain
those two collections of unattached scores, and they
do have a useful purpose, but the definition of set
is inadequate to accomodate those two collections.
.
- Follow-Ups:
- Re: set notation
- From: hagman
- Re: set notation
- References:
- set notation
- From: wellsoberlin
- set notation
- Prev by Date: Re: Rational numbers, irrational numbers: each dense in real numbers
- Next by Date: Re: colud you please send me.....
- Previous by thread: set notation
- Next by thread: Re: set notation
- Index(es):
Relevant Pages
|
