Hi, Paige --
Good comments about "There are so many
different factors..."
"To say that half the observations should
have positive errors and half
should have negative errors is to confuse median with mean."
should have negative errors is to confuse median with mean."
I used the word ABOUT intentionally to
distinguish from EXACTLY.
--Joe
----- Original Message -----
From: "Paige Miller" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, October 03, 2000 10:19
AM
Subject: Re: How many Olympic Medals should
Great Britain have won?
> > Hi, Graham --
> >
> > It's been a long time since I've heard any discussion about
> > UNDERACHIEVERS and OVERACHIEVERS. I've never been able to understand
> > the discussions.
> >
> > NO MATTER WHAT VALUE THE CORRELATION (SLOPE OF THE REGRESSION LINE) HAS we
> > know that the ALGEBRAIC SUM OF THE ERRORS IS ZERO. Now that says that
> > the SUM OF THE ABSOLUTE VALUES OF THE POSITIVE ERRORS IS EQUAL TO THE
> > SUM OF THE ABSOLUTE VALUES OF THE NEGATIVE ERRORS. THEN WE WOULD EXPECT
> > TO OBSERVE ABOUT ONE-HALF OF THE OBSERVATIONS TO HAVE POSITIVE ERRORS AND
> > ONE-HALF TO HAVE NEGATIVE VALUES.
> >
> > THEREFORE, FOR ALL CORRELATIONS (ZERO INCLUDED) WE SHOULD EXPECT TO
> > CONCLUDE THAT ABOUT ONE-HALF OF ALL CASES
> > WOULD BE CALLED "OVER-ACHIEVERS" AND ABOUT ONE-HALF WOULD BE CALLED
> > "UNDER-ACHIEVERS". DOES THAT DESIGNATION HAVE ANY OPERATIONALLY USEFUL
> > MEANING?
> >
> > It's been a long time since I've heard any discussion about
> > UNDERACHIEVERS and OVERACHIEVERS. I've never been able to understand
> > the discussions.
> >
> > NO MATTER WHAT VALUE THE CORRELATION (SLOPE OF THE REGRESSION LINE) HAS we
> > know that the ALGEBRAIC SUM OF THE ERRORS IS ZERO. Now that says that
> > the SUM OF THE ABSOLUTE VALUES OF THE POSITIVE ERRORS IS EQUAL TO THE
> > SUM OF THE ABSOLUTE VALUES OF THE NEGATIVE ERRORS. THEN WE WOULD EXPECT
> > TO OBSERVE ABOUT ONE-HALF OF THE OBSERVATIONS TO HAVE POSITIVE ERRORS AND
> > ONE-HALF TO HAVE NEGATIVE VALUES.
> >
> > THEREFORE, FOR ALL CORRELATIONS (ZERO INCLUDED) WE SHOULD EXPECT TO
> > CONCLUDE THAT ABOUT ONE-HALF OF ALL CASES
> > WOULD BE CALLED "OVER-ACHIEVERS" AND ABOUT ONE-HALF WOULD BE CALLED
> > "UNDER-ACHIEVERS". DOES THAT DESIGNATION HAVE ANY OPERATIONALLY USEFUL
> > MEANING?
Paige writes
> There are so many different factors
that go into the amount of medals
> won that it seems silly to perform a regression based upon population
> and GDP to use as predictors. Organization of Olympic Committees,
> training facility quality, programs for youths, weather, etc. all can
> affect the number of medals won, and then there is the factor of
> injuries, which to me seems like it cannot be modelled except as
> random noise.
>
> To say that half the observations should have positive errors and half
> should have negative errors is to confuse median with mean.
>
> --
> Paige Miller
> Eastman Kodak Company
> [EMAIL PROTECTED]
>
> "It's nothing until I call it!" -- Bill Klem, NL Umpire
> "Those black-eyed peas tasted all right to me" -- Dixie Chicks
>
>
> =================================================================
> Instructions for joining and leaving this list and remarks about
> the problem of INAPPROPRIATE MESSAGES are available at
> http://jse.stat.ncsu.edu/
> =================================================================
>
> won that it seems silly to perform a regression based upon population
> and GDP to use as predictors. Organization of Olympic Committees,
> training facility quality, programs for youths, weather, etc. all can
> affect the number of medals won, and then there is the factor of
> injuries, which to me seems like it cannot be modelled except as
> random noise.
>
> To say that half the observations should have positive errors and half
> should have negative errors is to confuse median with mean.
>
> --
> Paige Miller
> Eastman Kodak Company
> [EMAIL PROTECTED]
>
> "It's nothing until I call it!" -- Bill Klem, NL Umpire
> "Those black-eyed peas tasted all right to me" -- Dixie Chicks
>
>
> =================================================================
> Instructions for joining and leaving this list and remarks about
> the problem of INAPPROPRIATE MESSAGES are available at
> http://jse.stat.ncsu.edu/
> =================================================================
>
