[Tutor] Drawing confidence level ellipses

[SATYABRATA DATTA]

A model predicts value of some quantity A and B which need to be fitted to
the experimental 1-sigma,2-sigma etc.confidence intervals. I have a given
experimental data file containing the experimental output of A,B and
delta_chi_square Similar to this
A. B. Chi_sq
0.0001 0.170 5.883053e+02
0.0002 0.175 5.818523e+02
0.0003 0.180 5.756402e+02
0.0004 0.185 5.696054e+02
0.0005 0.190 5.638476e+02
0.0006 0.195 5.584292e+02
0.0007 0.200 5.532851e+02
0.0008 0.205 5.484670e+02
0.0009 0.210 5.439196e+02
0.0010 0.215 5.396868e+02
0.0011 0.220 5.342531e+02
0.0012 0.225 5.259659e+02
How to plot the confidence regions on the same modelled data plot by
matplotlib.