  Observations of the spatial distributions of young stars in star-forming
regions can be linked to the theory of clustered star formation using spatial
statistical methods. The MYStIX project provides rich samples of young stars
from the nearest high-mass star-forming regions. Maps of stellar surface
density reveal diverse structure and subclustering. Young stellar clusters and
subclusters are fit with isothermal spheres and ellipsoids using the Bayesian
Information Criterion to estimate the number of subclusters. Clustering is also
investigated using Cartwright and Whitworth's Q statistic and the inhomogeneous
two-point correlation function. Mass segregation is detected in several cases,
in both centrally concentrated and fractally structured star clusters, but a
few clusters are not mass segregated.
