Error analysis of nuclear mass fits

We discuss the least-squares and linear-regression methods, which are relevant for a reliable determination of good nuclear-mass-model parameter sets and their errors. In this perspective, we define exact and inaccurate models and point out differences in using the standard error analyses for them. As an illustration, we use simple analytic models for nuclear binding energies and study the validity and errors of models' parameters and uncertainties of its mass predictions. In particular, we show explicitly the influence of mass-number-dependent weights on uncertainties of liquid-drop global parameters.