  The stability of model parameters for a class of relativistic energy density
functionals, characterized by contact (point-coupling) effective inter-nucleon
interactions and density-dependent coupling parameters, is analyzed using
methods of statistical analysis. A set of pseudo-observables in infinite and
semi-infinite nuclear matter is used to define a quality measure $\chi^2$ for
subsequent analysis. We calculate uncertainties of model parameters and
correlation coefficients between parameters, and determine the eigenvectors and
eigenvalues of the matrix of second derivatives of $\chi^2$ at the minimum.
This allows to examine the stability of the density functional in nuclear
matter, and to deduce weakly and strongly constrained combinations of
parameters. In addition, we also compute uncertainties of observables that are
not included in the calculation of $\chi^2$: binding energy of asymmetric
nuclear matter, surface thickness of semi-infinite nuclear matter, binding
energies and charge radii of finite nuclei.
