SPSSX Discussion

Dispersion

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Siraj Ur-rehman

Dispersion

Dear Guys
I got this data from a student and he is asking about the three values
of Dispersion (73%, 99 and 205). I don't have any other info and can't
describe the three values of dispersion so please anyone know about then
let me know. Thanks

Avq. Min Max Dispersion
Cost per day ($) 107 46 898 73%, 99 and 205

Siraj

Hector Maletta

Re: Dispersion

I have sometimes seen the standard deviation referred to as "dispersion",
though it is quite unusual and rather old fashioned (I have only seen it in
old books). Also, all measures of variability (such as variance, std
deviation, range, interquartile range, etc.) are sometimes collectively
called "measures of dispersion".
Hector

-----Mensaje original-----
De: SPSSX(r) Discussion [mailto:[hidden email]] En nombre de Siraj
Ur-rehman
Enviado el: Tuesday, August 15, 2006 11:04 AM
Para: [hidden email]
Asunto: Dispersion

Dear Guys
I got this data from a student and he is asking about the three values
of Dispersion (73%, 99 and 205). I don't have any other info and can't
describe the three values of dispersion so please anyone know about then
let me know. Thanks

Avq. Min Max Dispersion
Cost per day ($) 107 46 898 73%, 99 and 205

Siraj

Siraj Ur-rehman

Re: Dispersion

In reply to this post by Siraj Ur-rehman

Hi Hector
Thanks for it but what could be these numbers (73%, 99 and 205) out of
different measure of dispersions? Please let me know if you can guess
about any statistic for these three numbers. Thanks

Siraj

-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of
Hector Maletta
Sent: Tuesday, August 15, 2006 11:36 AM
To: [hidden email]
Subject: Re: Dispersion

I have sometimes seen the standard deviation referred to as
"dispersion", though it is quite unusual and rather old fashioned (I
have only seen it in old books). Also, all measures of variability (such
as variance, std deviation, range, interquartile range, etc.) are
sometimes collectively called "measures of dispersion".
Hector

-----Mensaje original-----
De: SPSSX(r) Discussion [mailto:[hidden email]] En nombre de
Siraj Ur-rehman Enviado el: Tuesday, August 15, 2006 11:04 AM
Para: [hidden email]
Asunto: Dispersion

Dear Guys
I got this data from a student and he is asking about the three values
of Dispersion (73%, 99 and 205). I don't have any other info and can't
describe the three values of dispersion so please anyone know about then
let me know. Thanks

Avq. Min Max Dispersion
Cost per day ($) 107 46 898 73%, 99 and 205

Siraj

Edward Boadi

Re: Dispersion

In reply to this post by Siraj Ur-rehman

Siraj, I guess it will be difficult to guess what those numbers are with
knowing the data set from which those numbers were derived.

-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]]On Behalf Of
Siraj Ur-rehman
Sent: Tuesday, August 15, 2006 12:15 PM
To: [hidden email]
Subject: Re: Dispersion

Hi Hector
Thanks for it but what could be these numbers (73%, 99 and 205) out of
different measure of dispersions? Please let me know if you can guess
about any statistic for these three numbers. Thanks

Siraj

-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of
Hector Maletta
Sent: Tuesday, August 15, 2006 11:36 AM
To: [hidden email]
Subject: Re: Dispersion

I have sometimes seen the standard deviation referred to as
"dispersion", though it is quite unusual and rather old fashioned (I
have only seen it in old books). Also, all measures of variability (such
as variance, std deviation, range, interquartile range, etc.) are
sometimes collectively called "measures of dispersion".
Hector

-----Mensaje original-----
De: SPSSX(r) Discussion [mailto:[hidden email]] En nombre de
Siraj Ur-rehman Enviado el: Tuesday, August 15, 2006 11:04 AM
Para: [hidden email]
Asunto: Dispersion

Dear Guys
I got this data from a student and he is asking about the three values
of Dispersion (73%, 99 and 205). I don't have any other info and can't
describe the three values of dispersion so please anyone know about then
let me know. Thanks

Avq. Min Max Dispersion
Cost per day ($) 107 46 898 73%, 99 and 205

Siraj

Marta García-Granero

Re: Dispersion

In reply to this post by Siraj Ur-rehman

Hi

SUr> I got this data from a student and he is asking about the three values
SUr> of Dispersion (73%, 99 and 205). I don't have any other info and can't
SUr> describe the three values of dispersion so please anyone know about then
SUr> let me know.

SUr> Avq. Min Max Dispersion
SUr> Cost per day ($) 107 46 898 73%, 99 and 205

In my opinion, 73% could be the coefficient of variation
(100*SD/mean), and, perhaps, given that the data look quite skewed to
the right, "99 and 205" could be the interquartilic range (IQR), that
is: the interval formed by Q1 and Q3 (or P25 and P75, as you wish to
call them).

Just guessing...

--
Regards,
Dr. Marta García-Granero,PhD mailto:[hidden email]
Statistician

---
"It is unwise to use a statistical procedure whose use one does
not understand. SPSS syntax guide cannot supply this knowledge, and it
is certainly no substitute for the basic understanding of statistics
and statistical thinking that is essential for the wise choice of
methods and the correct interpretation of their results".

(Adapted from WinPepi manual - I'm sure Joe Abrahmson will not mind)

David C-3

Re: Dispersion

I believe Marta is correct. Believe it or not, as these msgs were
coming in I was preparing/reviewing for a course for the Fall semester
and in the Chapter I was reading (Research Methods for Public
Administrators (4th Ed.), O'Sullivan, et al, p 346), the author
mentions the "Tukey five-number summary" which includes:

Min
Max
Median (not Mean)
1st Quartile
3rd Quartile

This could be it; Marta's mention on what the percentage is could be
as good as any!

However, I'd tell/ask the student: "what in the heck is this and why
isn't it more descriptive?"

--
David Chapman
Research Associate, PhD Student
Dept of Urban Studies and Public Administration
College of Business and Public Administration
Old Dominion University
[hidden email]

On 8/15/06, Marta García-Granero <[hidden email]> wrote:

> Hi
>
> SUr> I got this data from a student and he is asking about the three values
> SUr> of Dispersion (73%, 99 and 205). I don't have any other info and can't
> SUr> describe the three values of dispersion so please anyone know about then
> SUr> let me know.
>
> SUr> Avq. Min Max Dispersion
> SUr> Cost per day ($) 107 46 898 73%, 99 and 205
>
> In my opinion, 73% could be the coefficient of variation
> (100*SD/mean), and, perhaps, given that the data look quite skewed to
> the right, "99 and 205" could be the interquartilic range (IQR), that
> is: the interval formed by Q1 and Q3 (or P25 and P75, as you wish to
> call them).
>
> Just guessing...
>
>
>
>
>
> --
> Regards,
> Dr. Marta García-Granero,PhD mailto:[hidden email]
> Statistician
>
> ---
> "It is unwise to use a statistical procedure whose use one does
> not understand. SPSS syntax guide cannot supply this knowledge, and it
> is certainly no substitute for the basic understanding of statistics
> and statistical thinking that is essential for the wise choice of
> methods and the correct interpretation of their results".
>
> (Adapted from WinPepi manual - I'm sure Joe Abrahmson will not mind)
>

--
David Chapman
Research Associate
E. V. Williams Center for Real Estate and Economic Development
College of Business and Public Administration
Old Dominion University
[hidden email]
757-683-5352

Siraj Ur-rehman

Re: Dispersion

In reply to this post by Siraj Ur-rehman

Thanks a lot Marta and David.

Siraj

-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of David C
Sent: Tuesday, August 15, 2006 12:31 PM
To: [hidden email]
Subject: Re: Dispersion

I believe Marta is correct. Believe it or not, as these msgs were coming in I was preparing/reviewing for a course for the Fall semester and in the Chapter I was reading (Research Methods for Public Administrators (4th Ed.), O'Sullivan, et al, p 346), the author mentions the "Tukey five-number summary" which includes:

Min
Max
Median (not Mean)
1st Quartile
3rd Quartile

This could be it; Marta's mention on what the percentage is could be as good as any!

However, I'd tell/ask the student: "what in the heck is this and why isn't it more descriptive?"

--
David Chapman
Research Associate, PhD Student
Dept of Urban Studies and Public Administration College of Business and Public Administration Old Dominion University [hidden email]

On 8/15/06, Marta García-Granero <[hidden email]> wrote:

> Hi
>
> SUr> I got this data from a student and he is asking about the three
> SUr> values of Dispersion (73%, 99 and 205). I don't have any other
> SUr> info and can't describe the three values of dispersion so please
> SUr> anyone know about then let me know.
>
> SUr> Avq. Min Max Dispersion
> SUr> Cost per day ($) 107 46 898 73%, 99 and 205
>
> In my opinion, 73% could be the coefficient of variation
> (100*SD/mean), and, perhaps, given that the data look quite skewed to
> the right, "99 and 205" could be the interquartilic range (IQR), that
> is: the interval formed by Q1 and Q3 (or P25 and P75, as you wish to
> call them).
>
> Just guessing...
>
>
>
>
>
> --
> Regards,
> Dr. Marta García-Granero,PhD mailto:[hidden email]
> Statistician
>
> ---
> "It is unwise to use a statistical procedure whose use one does not
> understand. SPSS syntax guide cannot supply this knowledge, and it is
> certainly no substitute for the basic understanding of statistics and
> statistical thinking that is essential for the wise choice of methods
> and the correct interpretation of their results".
>
> (Adapted from WinPepi manual - I'm sure Joe Abrahmson will not mind)
>

--
David Chapman
Research Associate
E. V. Williams Center for Real Estate and Economic Development College of Business and Public Administration Old Dominion University [hidden email]
757-683-5352