  In the light of the Planck 2015 results, we update simple inflationary models
based on the quadratic, quartic, Higgs and Coleman-Weinberg potentials in the
context of the Randall-Sundrum brane-world cosmology. Brane-world cosmological
effect alters the inflationary predictions of the spectral index ($n_s$) and
the tensor-to-scalar ratio ($r$) from those obtained in the standard cosmology.
In particular, the tensor-to-scalar ratio is enhanced in the presence of the
5th dimension. In order to maintain the consistency with the Planck 2015
results for the inflationary predictions in the standard cosmology, we find a
lower bound on the five-dimensional Planck mass ($M_5$). On the other hand, the
inflationary predictions laying outside of the Planck allowed region can be
pushed into the allowed region by the brane-world cosmological effect with a
suitable choice of $M_5$.
