Re: possible bug in errors in fitting routine

[Arun P. <ape...@lb...>]

On 12/09/2012 02:03 PM, Hans-Bernhard Bröker wrote:
> On 08.12.2012 21:00, Arun Persaud wrote:
> 
>> according to http://arxiv.org/abs/1210.3781 page 42 (between formulas D7
>> and D8) gnuplot outputs the wrong errors when errors in the raw data are
>> used during the fitting process.
> 
> It's a good deal less simple than the author of that paper makes it out
> to be.  The error reported by "fit" (as of the current development
> version: in its default state) only differs from the result desired by
> Mr. Young in the case where the data errors are clearly _not_ adequate,
> yielding a reduced chisq way off target.  Reporting the errors he wants
> would do the user an even bigger disservice in those cases than what
> gnuplot does now.
> 
> As a matter of fact, the Particle Data Book itself, possibly one of the
> biggest fitting jobs regularly performed in all of physics, uses the
> exact same procedue as gnuplot in those cases where the fits are too bad
> to be taken at face value.

Ok, just wanted to make you aware of this. Thanks for looking into it.

cheers
	
Arun