METHODS OF SAMPLING DISCRETE CONTAGIOUS
DISTRIBUTIONS
Dilermando PERECIN[1]
Édemo João FERNANDES[2]
§ ABSTRACT: The contagious
distributions are common in biology and, in particular, in agronomy, by
instance: spatial distribution on spatial pattern of weeds, insects, by area,
plant etc. The main characteristics of such data or distribution is the
formation of clumps and, in consequence, showing variance larger than mean. Two
methods of sampling are analysed. One, that take a large sample unit, with the
objective of to incorporate all the correlation among adjacent elements. The
other, that take a suficiently small size for the sample unit, for reaching a
distribution similar to Poisson. It is advocated that, for practical purpose,
the second method is very useful, because it eliminates the necessity of
knowing and estimating the parameters of the contagious distribution. The
latter, is not stable varying with the size of the sample.
§
KEYWORDS: Contagious distribution;
relation variance/mean; sampling; overdisperson.