Z' and anomalous gauge coupling effects at LEP2 and their separation

In the case of the process $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}$, we study the sensitivity to either $Z^{\mathrm{\prime }}$ or anomalous gauge coupling effects of two new observables, ${\sigma }_{+}$ and ${\sigma }_{-}$, conveniently defined for such kind of analysis. We discuss general properties of the deviations of these observables from the Standard Model predictions, and derive the model-independent bounds on the relevant parameters allowed by present and foreseeable LEP2 data. We also discuss the possibility of separating the two kinds of effect.