[Ifeffit] What confidence limit is implied in the error bars for least-squares fitting in Athena

[Bruce Ravel]

On Thursday 02 October 2008 18:06:19 Matt Newville wrote:
> Does it?  I thought it used data_uncertainty=1 unless the uncertainty
> was explicitly specified.  Does Athena use a value determined from the
> sigma when merging data, or is something?   Should I read the Users
> Guide more closely?

Chapter 8 of the Ifeffit Reference Manual is a bit ambiguous about
what is reported as an error bar by minimize, but it does lead one to
believe that the error bars have been rescaled by the suqare root of
reduced chi-square -- like the feffit function.

B


-- 
 Bruce Ravel  ------------------------------------ bravel at bnl.gov

 National Institute of Standards and Technology
 Synchrotron Methods Group at NSLS --- Beamlines U7A, X24A, X23A2
 Building 535A
 Upton NY, 11973

 My homepage:    http://xafs.org/BruceRavel
 EXAFS software: http://cars9.uchicago.edu/~ravel/software/exafs/