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Re: REGRESS Question [message #32046 is a reply to message #31982]

Fri, 06 September 2002 00:26

Mike Alport
Messages: 8
Registered: December 1998

Junior Member

I think Bill may have a point - either R or R^2 is sometimes used as a
measure of "Goodness of Fit". One way to check this would be to compare this
quantity from both programs to eg 5 dec places and see if one is the SQRT of
the other.
Mike

"Bill" <wclodius@lanl.gov> wrote in message
news:3D7794C1.17DD18AB@lanl.gov...
>
>
> David Fanning wrote:
>
>> Folks,
>>
>> I have a client who has asked me to create a pixel density
>> function between two images and then perform a regression
>> analysis on the resulting distribution. No problem doing all
>> this, but she finds that the results of my regression analysis
>> differ from the same analysis performed in other statistics
>> packages. In fact, three different packages give the same
>> answer, and then there is IDL. :-(
>>
>> For example, if the other packages calculate a "goodness
>> of fit" of 0.95, IDL might report 0.97.
>>
>> Here is my question. Are there any known problems with REGRESS?
>> Or, can I assume that this problem comes from my own mathematical
>> ignorance?
>>
>> Cheers,
>>
>> David
>
> <snip>
>
> Almost any package can have problems, but the original REGRESS in
> Bevington has stood the test of time. IDL's version works for me, but it
> is possible that the introduced some problems. One thing that bothers
> me is tha 0.95 is to a good approximation 0.97^2. Could you be fitting
> the square root of the customer's data.
>

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[Message index]

		REGRESS Question By: David Fanning on Wed, 04 September 2002 14:21
		Re: REGRESS Question By: Mike Alport on Fri, 06 September 2002 00:26
		Re: REGRESS Question By: julia[1] on Thu, 05 September 2002 11:31
		Re: REGRESS Question By: William Clodius on Thu, 05 September 2002 10:31
		Re: REGRESS Question By: justspam03 on Wed, 22 October 2003 07:01
		Re: REGRESS Question By: wmconnolley on Wed, 22 October 2003 06:03
		Re: REGRESS Question By: Chris Lee on Wed, 22 October 2003 03:44
		Re: regress question By: Wout De Nolf on Mon, 01 December 2008 00:38
		Re: regress question By: mccreigh on Sun, 30 November 2008 23:42
		Re: regress question By: Kenneth P. Bowman on Sat, 29 November 2008 07:58
		Re: regress question By: Brian Larsen on Thu, 27 November 2008 07:37
		Re: regress question By: Wout De Nolf on Thu, 27 November 2008 02:47

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