fCressieRead: Cressie and Read

In OnomasticDiversity: Onomastic Diversity Measures

Cressie and Read

Description

This function obtains the Cressie and Read statistics introduced by Noel Cressie and Timothy Read. It is a method for quantifying species biodiversity that can be adapted to the context of onomastics.

Usage

fCressieRead(x, number, population, ni, location, lambda)

Arguments

x	dataframe of the data values.
number	name of a variable which represents number of individuals of each species.
population	name of variable which represents total number of individuals.
ni	name of variable which represent number of species.
location	name of variable which represent represents the grouping element.
lambda	free parameter.

Details

For a community i, Cressie and Read (1984) introduced the following parametric form for a generalised statistic I_n (\lambda) = \frac{2}{\lambda(\lambda+1)} \sum_{k\in S_i} { n_{ki} \left[ \left(\frac{n_{ki}}{n/S_i}\right)^\lambda-1\right]}, where n_{ki} represents the number of individuals of species k in a sample (in the population is N_{ki}), S_i represents all species at the community, species richness, and \lambda is a free parameter.

Varying the value of \lambda gets different statistics. If \lambda= -1 and \lambda= 0, I_n(\lambda) is not defined, but in any case, limits \lambda = -1 and \lambda = 0 can be taken.

In onomastic context, n_{ki} (\approx N_{ki}) denotes the absolute frequency of surname k in region i (\approx community diversity context i).

Value

A dataframe containing the following components:

location	represents the grouping element, for example the communities / regions.
cressieRead	the value of Cressie and Read statistics.

Author(s)

Maria Jose Ginzo Villamayor

References

Cressie, Noel and Read, Timothy RC (1984) Multinomial goodness-of-fit tests. Computational Statistics and Data Analysis, 46(3), 440–464.

See Also

fHill

Examples

data(surnamesgal14)
result = fCressieRead(x= surnamesgal14 , number="number",
population="population", location = "muni", ni="ni",
lambda = 2)
result

OnomasticDiversity documentation built on May 29, 2024, 1:32 a.m.