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statistic

Change the fit statistic in use.

XSPEC> statistic [chi | cstat]

The options are chi-squared (chi) or C-statistic (cstat). Note that the C-statistic has a couple of limitations : a) it cannot be used on background-subtracted data; b) if the calculated model goes to zero in any channel, then the format statistic goes to infinity - in practice this is trapped and a large value of the statistic should result.



Keith Arnaud (kaa@genji.gsfc.nasa.gov)
Wed May 28 10:59:33 EDT 1997