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A More Powerful Test for Dispersion Using Distance Measurements
Author(s) -
Johnson Roger B.,
Zimmer William J.
Publication year - 1985
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1938029
Subject(s) - dispersion (optics) , index of dispersion , mathematics , statistics , index (typography) , power (physics) , test (biology) , statistical physics , ecology , computer science , physics , biology , optics , poisson regression , population , demography , quantum mechanics , sociology , world wide web
A new index of dispersion I is proposed. I is based on distance measurements, has computable moments, and is asymptotically normal under the important pattern assumptions. I also provides a test for dispersion. The power of the I test and the asymptotic relative efficiency were computed with respect to two previously proposed tests for dispersion. It was found that the test based on I is more powerful than the other tests for several alternative hypotheses. In addition, I is easily extendable and applicable to m dimensions, whereas other indices and tests relate only to two dimensions.