From: mcclella@yertle.Colorado.EDU (Gary McClelland)
Subject: Re: F distribution and relation to Beta
Organization: University of Colorado, Boulder
Date: Sat, 23 Jan 1993 23:43:35 GMT

an7855@anon.penet.fi writes:

>> 
>> pddxt@chalk.cpceng.cpc.gmeds.com (Dino Triantos 575-4386) writes:
>> 
>> >I'm working on a problem in Mood, Graybill and Boes that asks to find the
>> >relationship between the F and Beta distributions.  The problem asks:  If 
>> >X has an F distribution with m and n degrees of freedom, show that
>> > 
>> >		        mX/n
>> >		 W =   -------       has a Beta distribution.
>> >		      1 + mX/n
>> 
>> >Any suggestions or solutions would be greatly appreciated! 
>> 
>> >Dinos Triantos
>> >GM/Midsize Automotive Division 
>> >Vehicle Systems Analysis
>> >C-P-C Engr. Center Rm# G241
>> >Fax: (313) 575-7270
>> >E-mail: pddxt@cpceng.cpc.gmeds.com
>> 
>> Is this a homework problem or will the solution to this
>> statistical issue help GM build better cars?  The net has
>> informal prohibitions against providing answers to homework
>> problems.  The problem you raise is a very standard homework
>> assignment in undergraduate statistics classes.  When I did it as
>> a homework problem many years ago I remember that it was a bit
>> easier to do it as W = 1/(1+(m/n)F).  It won't help you solve it,
>> but a useful insight is that W is often known as R^2.  Good luck!
>> 

>    What rock did this respondent crawl out from under of? 

>    [I've carefully removed his identity from his response.  
>I'm more concerned with what he represent that who he is.]

Then I'll carefully put the identity back in.  My name is Gary
McClelland and I'm a professor at the Univ of Colorado.  Who may
I ask is an7855@anon.penet.fi?  Do you have the courage of your
convictions Mr. or Ms. Anon?

>    Here we have an individual working in industry who has a statistics 
>question and some clown decides to disgrace the profession by going beyond 
>even stereotypical behavior to insult the client (Is this a homework 
>problem or will the solution to this statistical issue help GM build 
>better cars?)  

As a professor, I do not think it appropriate for the net to
provide students with answers to homework problems.  The original
poster indicated that it was a problem from a standard
statistical textbook.  It appears in all respects to be a
homework problem.  The same poster posted a similar note asking
about a different homework-like problem within the week.  Perhaps
I goofed in inferring from so little data that a trend was
developing, but I thought it appropriate to suggest that if this
were homework, that responses from the net would not be
appropriate.  But perhaps I'm wrong on net opinion.  Should we
take a vote as to whether we should be answering homework
problems?

I've also served as consultalnt for the General Motors Research
Labs.  I know that they have some _very_ competent statisticians. 
If the poster needs help with work-related statistical issues,
then there are better places within GM to seek answers to those
questions rather than appealing to the net.
                                         
>  Put the two together and you've got intellectual 
>bullying (or incompentence, depending on the reason for the 
>misinformation) at its worst.  And no one bothers to take the respondent 
>to task!

At least no one not willing to hide behind an anonymous name and
address...

>    I've never posted to this group because of my anger at the amount of 
>abuse and misinformation that gets passed out. I've prefered to send my 
>advice by private e-mail and take part in a real dialogue with my 
>"clients".  

One nice thing about postings to the net, as opposed to private
e-mail, is that postings are subject to a form of peer review.

>    Wouldn't it have been nice if Mr. Triantos had learned that 
>statisticians were only too happy to help those who were eager and willing 
>to learn? 

There is a lot of evidence that suggests that students will learn
and retain better problems that they solve on their own as
opposed to having someone else solve the problems for them. 

>-------------------------------------------------------------------------
>To find out more about the anon service, send mail to help@anon.penet.fi.
>Due to the double-blind system, any replies to this message will be anonymized,
>and an anonymous id will be allocated automatically. You have been warned.

Maybe anonymous postings are useful for some of the lurid alt.*
newsgroups, but do we really need to hide behind anonymous IDs
for sci.math.stat?

gary mcclelland
univ of colorado
mcclella@yertle.colorado.edu
Newsgroups: sci.math.stat