  In the extra dimension models of ADD and RS we study the dependence of the
various parton distribution functions on observable of Drell-Yan process to NLO
in QCD at LHC and Tevatron energies. Uncertainties at LHC due to factorisation
scales in going from leading to next-to-leading order in QCD for the various
distributions get reduced by about 2.75 times for a $\mu_F$ range $0.5 ~Q <
\mu_F < 1.5 ~Q$. Further uncertainties arising from the error on experimental
data are estimated using the MRST parton distribution functions.
