NPetersen {recapr}

Petersen Estimator

Description

Calculates the value of the Petersen estimator for abundance in a mark-recapture experiment, with given values of sample sizes and number of recaptures. The Petersen estimator is the MLE, but is typically outperformed by the Chapman estimator.

Usage

NPetersen(n1, n2, m2)

Arguments

n1

Number of individuals captured and marked in the first sample. This may be a single number or vector of values.

n2

Number of individuals captured in the second sample. This may be a single number or vector of values.

m2

Number of marked individuals recaptured in the second sample. This may be a single number or vector of values.

Value

The value of the Petersen estimator, calculated as n1*n2/m2

Note

Any Petersen-type estimator (such as this) depends on a set of assumptions:

• The population is closed; that is, that there are no births, deaths, immigration, or emigration between sampling events

• All individuals have the same probability of capture in one of the two events, or complete mixing occurs between events

• Marking in the first event does not affect probability of recapture in the second event

• Individuals do not lose marks between events

• All marks will be reported in the second event

Author(s)

Matt Tyers

See Also

NChapman, NBailey, vPetersen, sePetersen, rPetersen, pPetersen, powPetersen, ciPetersen

Examples

NPetersen(n1=100, n2=100, m2=20)