reviews [@fluc1]) is motivated by expectations of anomalies in the vicinity of the onset of deconfinement [@ood] and in the case when the expanding system goes through the transition line between the quark-gluon plasma and the hadron gas [@fluc2]. Furthermore, it is expected that a critical point of strongly interacting matter may be signaled by a characteristic pattern in fluctuations [@fluc3].

A convenient measure of the particle number fluctuations is the scaled variance, $\omega \equiv Var(N)/\langle N\rangle$, defined in terms of the mean value, $\langle N\rangle$, and variance, $Var(N)\equiv \langle N^2\rangle - \langle N\rangle^2$. The scaled variance equals to 1 for the ideal Boltzmann gas in the grand canonical ensemble (GCE). The deviations of $\omega$ from unity in the hadron-resonance gas (HG) come due to Bose and Fermi statistics, resonance decays (see, e.g., Ref. [@fluc1]), and exactly enforced conservations laws [@CE; @res_CE; @res_MCE]. Previous study [@res_MCE] has shown a rather rapid convergence of the scaled variances to asymptotic values. Finite system size effects can therefore be ignored for central collisions of heavy nuclei.

The effect of Bose and Fermi statistics can be seen in the primordial (before resonance decay) values of the scaled variances in the GCE (see, e.g., Ref. 