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THE SPATIAL AUTOCORRELATION COEFFICIENT MORAN'S I UNDER HETEROSCEDASTICITY
Author(s) -
WALDHÖR THOMAS
Publication year - 1996
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/(sici)1097-0258(19960415)15:7/9<887::aid-sim257>3.0.co;2-e
Subject(s) - heteroscedasticity , statistics , autocorrelation , mathematics , econometrics , spatial analysis , population , covariance , randomness , statistical hypothesis testing , demography , sociology
The spatial distribution of rates used in epidemiology often raises questions concerning the randomness of the observed pattern. In order to provide a first answer to this kind of question, the well‐known spatial autocorrelation coefficient Moran's I is frequently used. Unfortunately, under heteroscedasticity, that is, unequal variances of the rates due to different population sizes, the moments of the test distribution of Moran's I under H 0 differ from the usually used moments. To obtain a less biased test, it is proposed in this paper and validated by simulation results, to approximate the moments of Moran's I by means of incorporating population size into the covariance matrix of the rates.