Student Drop-Out Rates...why?

On Tue, 23 Aug 2005 20:36:04 -0700, "Seth Masia"
wrote:

Umm -- the definition of median is that half the range is higher and half is
lower. This means that if the median is $42,000, and there are 100 million
households, then 50 million households make more than $42k.

That sounds like an average rather than a median.
If you take the lowest number income to the highest and put them in
order the number in the middle would be the median.


In fact the average income is higher, because it's pulled up by the very
wealthy households making millions per year, and that's not offset by

That would pull the median up more than the average.
Average is the total income of all the households divided by the
number of households. One family making $500,000,000 against several
million in the $40,000 range would have little effect on the average
and a big hit on median.

households making negative income (we don't allow individuals to rack up
millions in debt -- only corporations). The mathematical average might be
around $60k or even higher.

snip

Jay Honeck wrote:

If I could do it, anyone can do it.


There are many people out there who should never get near an airplane
and many who are just not mentally or physically equipped to think in
three dimensions safely.


Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

That sounds like an average rather than a median.

No, that's the definition of median.

One family making $500,000,000 against several
million in the $40,000 range would have little effect on the average
and a big hit on median.

Nope. Backwards.

The "median" is the value of the sample in the middle. If you take the
highest number and increase it by a factor of a bazillion, the median is
unchanged.

Jose
--
Quantum Mechanics is like this: God =does= play dice with the universe,
except there's no God, and there's no dice. And maybe there's no universe.
for Email, make the obvious change in the address.

Roger wrote:

If you take the lowest number income to the highest and put them in
order the number in the middle would be the median.

Correct.

Average is the total income of all the households divided by the
number of households. One family making $500,000,000 against several
million in the $40,000 range would have little effect on the average
and a big hit on median.

Nope. If you had two families making $20,000, one making $40,000, and two making
$80,000, the median would be $40,000 and the average would be $48,000. If one of
those top-earners gets a raise to $100,000, the median is still $40,000, but the
average goes up to $52,000.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

On Wed, 24 Aug 2005 23:36:23 -0400, Roger
wrote:

On Tue, 23 Aug 2005 20:36:04 -0700, "Seth Masia"
wrote:

Umm -- the definition of median is that half the range is higher and half is
lower. This means that if the median is $42,000, and there are 100 million
households, then 50 million households make more than $42k.

That sounds like an average rather than a median.
If you take the lowest number income to the highest and put them in
order the number in the middle would be the median.

This is correct only if "the number in the middle" means half of the
sequence of numbers are below it and half are above it. Such a
"median" may or may not also be the "mean".

Jim wrote:

This is correct only if "the number in the middle" means half of the
sequence of numbers are below it and half are above it.

Actually half the numbers are less than or equal to it and half are greater than
or equal to it.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

On Thu, 25 Aug 2005 14:46:58 GMT, George Patterson
wrote:

Jim wrote:

This is correct only if "the number in the middle" means half of the
sequence of numbers are below it and half are above it.

Actually half the numbers are less than or equal to it and half are greater than
or equal to it.

Much better.


George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.