Re: [Phys-L] Model Selection Statistics

[Paul Nord <Paul.Nord@valpo.edu>]

>  This is an attempt to find the best
> value for a physical parameter based on spectra from a particle physics
> detector.
OK.
> Actually, it's not about prediction.
I'm surprised, and not 100% convinced.  Are we perhaps using
the word "prediction" in different ways?  In particular, what
are you going to do with the fitted parameter?  If you publish
it, what are your readers going to do with it?  AFAICT real-
world science is all about making predictions.  If the parameter
is not going to be used for something, what's the point?
  This idea sometimes gets lost in cookbook classroom
  experiments, where the only goal is to get a number
  that agrees with the expected number, but IMHO that
  is not good science and not good pedagogy.


Fair enough.  In our case the particle mass is well known.  We're trying to
study production asymmetry as a function of polarization which may depend
on beam energy.

And I just learned that my colleague is "tuning" the number of parameters
in the background fit for every data set until the chi squared is small and
can then be "ignored."

As Sammy pointed out a few weeks ago, we really do enjoy learning from your
posts.  And I'm really not writing things like the above just to upset
you.  It's a true story.  That seriously just happened.

Paul