Interpoint squared distance as a measure of spatial clustering.
The expectation and variance for the mean interpoint squared distance are presented. In order to evaluate these expressions it is necessary to calculate the moments of a bivariate uniform distribution defined over an arbitrary polygon. Expressions for these moments are presented, allowing the mean interpoint squared distance to be used as a measure of spatial clustering. The distribution and power of this test statistic is explored on the unit square, and the spatial distribution of 11 cases of non-Hodgkin's lymphoma is investigated to illustrate an application of the approach.
Selvin
S
S
Department of Biomedical and Environmental Health Sciences, University of California, Berkeley, CA 94720.
Schulman
J
J
Merrill
D W
DW
D016000:Cluster Analysis; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000453:epidemiology; D008433:Mathematics; D012495:San Francisco / Q000453:epidemiology