> Each time I reopen analysis and setup the same fitting procedure for the
> same data I get the same fitting parameters (as one would expect) but
> with different fit errors.
>
> Given that the regression parameter estimates don't change each time I
> do this then I wouldn't expect the fitting error to change either.
The error is varying because of the noise estimates that we use to
calculate the Chi square error value. - The noise acts as a significance
baseline. The noise estimate is based upon the intensity distribution of a
random sampling of the spectrum data points and thus can vary a bit each
session. Even with this variation, the worst fitting graphs will remain
the worst.
As an initial step we can increase the number of sampled points to make
the estimate more consistent, but for the next release we'll probably put
in better noise level management.
> I have deliberately omitted the use of any error values in the 'series
> condition points' (Data analysis -> Rate analysis -> Edit Exp. Series)
> as I gather these have no impact on the fitting procedure or the fitting
> error at this stage.
Indeed. I'll discuss with Wayne how we could incorporate these.
Tim
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Dr Tim Stevens Email: [log in to unmask]
Department of Biochemistry [log in to unmask]
University of Cambridge Phone: +44 1223 766022 (office)
80 Tennis Court Road +44 7816 338275 (mobile)
Old Addenbrooke's Site +44 1223 364613 (home)
Cambridge CB2 1GA WWWeb: http://www.bio.cam.ac.uk/~tjs23
United Kingdom http://www.pantonia.co.uk
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