  I give an estimate for the skewness and the kurtosis of the baryon number
distribution in two representative models; i.e., models of a hadron resonance
gas and relativistic mean-field nuclear matter. I emphasize formal similarity
between these two descriptions. The hadron resonance gas leads to a deviation
from the Skellam distribution if quantum statistical correlation is taken into
account at high baryon density, but this effect is not strong enough to explain
fluctuation data seen in the beam-energy scan at RHIC/STAR. In the calculation
of mean-field nuclear matter the density correlation with the vector
$\omega$-field rather than the effective mass with the scalar $\sigma$-field
renders the kurtosis suppressed at higher baryon density so as to account for
the experimentally observed behavior of the kurtosis. We finally discuss the
difference between the baryon number and the proton number fluctuations from
correlation effects in isospin space. The numerical results suggest that such
effects are only minor even in the case of complete randomization of isospin.
