Re: Fixed vs. floating offsets

From: Lifan Wang (lifan@panisse.lbl.gov)
Date: Wed Feb 19 2003 - 15:03:28 PST

  • Next message: Robert A. Knop Jr.: "Re: Fixed vs. floating offsets"

    Rob,

    > There is no "right" way to do this that is utterly pure as the driven
    > snow statistically. Treating every supernova in a purely consistent
    > manner gives results that are obviously plain wrong, as the attached

      One thing I am not clear is the problem with having all the SNe with
    floating base line. I expect having an extra parameter only to reduce
    the fitting errors, although the best fit may prove to be quite
    irrelavent, the fit itself should always be an improvement. So can
    you please explain what is exactly bothering you here.

      For 92ag, I am surprised and bothered by the fact that your best fit
    needs a baseline offset of only 0.03. It seems to me that your other
    fit (with fixed baseline) actully did not converge to the real minimum
    chi^2. One way to see this is to add 0.03 to your best fit (with floating
    zero baseline) which then gives a fit with the baseline fixed to zero.
    Visually, I would expect this to be a much better fit than the fit given
    in the figure with fixed zero.

    Lifan



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