  We propose a scale-dependent cosmology in which the Robertson--Walker metric
and the Einstein equation are modified in such a way that $\Omega_0$, $H_0$ and
the age of the Universe all become scale-dependent. Its implications on the
observational cosmology and possible modifications of the standard Friedmann
cosmology are discussed. For example, the age of the Universe in this model is
longer than that of the standard model.
