  [Slightly Abridged] We present a detailed statistical analysis of the column
densities, N, and Doppler parameters, b, of MgII absorbing clouds at redshifts
0.4<z<1.2. We use the HIRES/Keck data and Voigt profile (VP) fitting results
presented by Churchill & Vogt (Paper I). The sample is comprised of 175 clouds
from 23 systems along 18 quasar lines of sight. In order to understand whether
inferred conditions could be "false", we performed extensive simulations of our
VP analyses. In brief, we find: (1) N(FeII) and N(MgII) are correlated at the
9-sigma level. There is a 5-sigma anti-correlation between N(MgI)/N(MgII) and
N(MgII). (2) Power-law fits to the distributions of N(MgII), N(FeII), and
N(MgI) yielded power-law slopes of -1.6, -1.7, and -2.0. (3) The modes of the
Doppler parameter distributions were <b>~5 km/s for MgII and FeII and <b>~7
km/s for MgI. The clouds are consistent with being thermally broadened, with
temperatures in the 30-40,000K range. (4) A two-component Gaussian model to the
velocity two-point correlation function yielded velocity dispersions of 54 km/s
and 166 km/s. The narrow component has roughly twice the amplitude of the
broader component. The width and amplitude of the broader component decreases
as equivalent width increases. (5) From photoionization models we find that the
column density ratios are most consistent with photoionization by the
extragalactic background, as opposed to stars. Based upon N(MgI)/N(MgII), it
appears that at least two-phase ionization models are required to explain the
data.
