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A New Method of Assessing Contagion, Applied to a Distribution of Redear Sunfish
Author(s) -
Ghent A. W.,
Grinstead B.
Publication year - 1965
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1965)94[135:anmoac]2.0.co;2
Subject(s) - negative binomial distribution , poisson distribution , randomness , statistics , mathematics , grid , statistical physics , binomial distribution , intersection (aeronautics) , point (geometry) , distribution (mathematics) , physics , mathematical analysis , geometry , geography , cartography
The method of binomial corner‐association analysis proposed in this paper is applicable to data from grids of contiguous cells, all or most of which are sampled. After sampling, the frequency distribution of cells at successive densities is grouped into a series of successive density categories. A separate binomial analysis is then conducted for each density category, in which the unit of observation is the number, from 0 to 4, of cells of the same density category which occur around each point of intersection on the grid. Applied to a distribution of the redear sunfish (Lepomis microlophus (Günther)) in a small lake in Oklahoma, the method revealed that unoccupied cells, and cells occupied at medium and at high densities, were contagiously distributed; low density cells, however, were acceptably random. The rationale of this analytical method is compared with that of inherently single‐dimensioned analyses such as the Poisson and negative binomial. Corner‐association analysis is shown to be inherently two‐dimensional, and to have the additional advantage of focussing attention upon the interaction of the species and the environment, such interactions producing contagion at some density levels and randomness at others.