  We examine the interpretation of individual phase-space trajectories of the
Wigner function as corresponding to possible outcomes of single experimental
trials. To this end, we investigate the relation between the true (measured)
particle number distribution $P_n$ for a single-mode state and that obtained by
discretely binning the individual stochastic realisations of squared mode
amplitudes $|\alpha|^2$ of the sampled Wigner distribution $W(\alpha)$, which
we denote via $\tilde{P}_n$. We provide an operational definition of
$\tilde{P}_n$ in terms of the underlying Wigner function, which allows us to
explicitly calculate the overlap between the two number distributions and hence
quantify the statistical distance between them. We find that there is indeed a
close quantitative correspondence between $P_n$ and $\tilde{P}_n$ for a wide
range of states, justifying the broadly accepted view that, for highly occupied
modes, individual stochastic realisations of Wigner trajectories should
approximately correspond to outcomes of single experiments. However, we also
find counterexamples for which high mode occupation may not be sufficient for
such an interpretation, we find instead that a more relevant and sufficient
requirement is the smoothness and broadness of the Wigner function $W(\alpha)$
for the state of interest relative to the scale of oscillations of the Wigner
functions for the relevant Fock states.
