  We perform three-dimensional (3D) compressible MHD simulations over many
dynamical times for an extended range of sonic and Alfven Mach numbers and
analyze the statistics of 3D density and 2D column density, which include
probability distribution functions, spectra, skewness, kurtosis, She-Leveque
exponents, and genus. In order to establish the relation between the statistics
of the observables, i.e. column densities, and the underlying 3D statistics of
density, we analyze the effects of cloud boundaries. We define the parameter
space for 3D measures to be recovered from column densities. In addition, we
show that for subsonic turbulence the spectra of density fluctuations are
consistent with k^-7/3 in the case of a strong magnetic field and k^-5/3 in the
case of a weak magnetic field. For supersonic turbulence we confirm the earlier
findings of the shallow spectra of density and Kolmogorov spectra of the
logarithm of density. We find that the intermittencies of the density and
velocity are very different.
