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The Index-of-Dispersion Test Revisited

  • D. Pfeifer
  • H. Ortleb
  • U. Schleier-Langer
  • H.-P. Bäumer
Conference paper
Part of the Studies in Classification, Data Analysis, and Knowledge Organization book series (STUDIES CLASS)

Summary

In quantitative ecology the classical index-of-dispersion is widely used for testing the hypothesis of spatial randomness. However, spatial aggregation of individuals is often observed in field experiments, so that the test will frequently reject the hypothesis without indicating any alternatives. In this paper we consider a modified index-of-dispersion test which allows for testing the hypothesis of a spatial Poisson point process with intensity measure having a density λ(x) of the form
$$ \lambda (x)\, = \,\sum\limits_{j = 1}^n {a_i f_j (x),\,\,\,x \in \mathbb{R}^2 } $$
with known non-negative regression functions f j (x) and unknown non-negative parameters a j which are to be estimated by the observed data. This model includes the classical case for n = 1 and f 1(x) = 1. Further applications to testing local geographical influences on health data are also pointed out.

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Copyright information

© Springer-Verlag Berlin · Heidelberg 1996

Authors and Affiliations

  • D. Pfeifer
  • H. Ortleb
  • U. Schleier-Langer
    • 1
  • H.-P. Bäumer
    • 2
  1. 1.Fachbereich Mathematik, Carl von OssietzkyUniversität OldenburgOldenburgGermany
  2. 2.Hochschulrechenzentrum, Carl von Ossietzky Universität OldenburgOldenburgGermany

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