  In the atmospheric neutrino experiments the primary problems are the huge
uncertainties of flux, very rapid fall of flux with increase of energy, the
energy dependent wide resolutions of energy and zenith angle between true
neutrinos and reconstructed neutrinos. These all in together make the choice of
binning of the data for chi-square analysis complicated. The large iron
calorimeter has the ability to measure the energy and the direction of the muon
with high resolution. From the bending of the track in the magnetic field it
can also distinguish its charge. We have analyzed the atmospheric neutrino
oscillation generating events by Nuance and then considering the muons produced
in the charge current interactions as the reconstructed neutrinos. This
practically takes into account the major problem of wide resolutions. We have
binned the data in three ways: i) in the grids of $\log E -\log L$ plane, ii)
in the grids of $\log E -\cos\theta_{\rm zenith}$ plane, and iii) in the bins
of $\log (L/E)$. We have performed a marginalized $\chi^2$ study over $\Delta
m_{32}^2, ~\theta_{13}$ and $\theta_{23}$ for neutrinos and anti-neutrinos
separately for each method and finally compared the results.
