Example of cstat result

XSPEC12>statistic cstat
Warning: Cstat statistic is only valid for Poisson data.
cstat statistic: variance weighted using standard weighting

C-statistic = 54.29 using 60 PHA bins and 58 degrees of freedom.

Warning: Cstat statistic is only valid for Poisson data.

Current data and model not fit yet.
XSPEC12>fit

C-Statistic Lvl Par # 1 2
47.1975 -2 2.25226 357.979
46.9197 -2 2.23793 301.834
46.7884 -2 2.22679 262.471
46.7104 -2 2.21809 235.235
46.6645 -2 2.21132 215.885
46.6374 -2 2.20607 201.888
46.6212 -2 2.20199 191.612
46.6116 -2 2.19883 183.977
==============================
Variances and Principal Axes
1 2
4.4503E-05| -1.0000 0.0004
6.4203E+04| -0.0004 -1.0000
------------------------------

========================
Covariance Matrix
1 2
1.019e-02 2.553e+01
2.553e+01 6.420e+04
------------------------

========================================================================
Model powerlaw<1> Source No.: 1 Active/On
Model Model Component Parameter Unit Value
par comp
1 1 powerlaw PhoIndex 2.19883 +/- 0.100969
2 1 powerlaw norm 183.977 +/- 253.384
________________________________________________________________________

C-statistic = 46.61 using 60 PHA bins and 58 degrees of freedom.

Warning: Cstat statistic is only valid for Poisson data.

XSPEC12>