  By using a correlated many body method and using the realistic van der Waals
potential we study several statistical measures like the specific heat,
transition temperature and the condensate fraction of the interacting Bose gas
trapped in an anharmonic potential. As the quadratic plus a quartic confinement
makes the trap more tight, the transition temperature increases which makes
more favourable condition to achieve Bose-Einstein condensation (BEC)
experimentally. BEC in 3D isotropic harmonic potential is also critically
studied, the correction to the critical temperature due to finite number of
atoms and also the correction due to inter-atomic interaction are calculated by
the correlated many-body method. Comparison and discussion with the mean-field
results are presented.
