int.est.crM0: Mark Recapture Model M0 Abundance Estimation: Interval...

In dill/wisp: Wildlife Simulation Package (wisp)

Description

This function estimates a confidence interval for group abundance from mark recapture method M0.

Usage

        int.est.M0(samp, init.N = -1, ci.type = "boot.nonpar", nboot = 999, vlevels = c(0.025, 0.975),
                   plot = FALSE, Chapmod = FALSE, numerical = FALSE, seed=NULL)

Arguments

samp	object of class 'sample.crM0´.
init.N	starting value of N used by the maximum likelihood optimisation routine
ci.type	method for constructing the confidence interval. Possible methods are * 'boot.par´ gives a parametric bootstrap CI, * 'boot.nonpar´ gives a nonparametric bootstrap CI, * 'normal´ gives a CI based on the assumption that the estimator is normally distributed (2 capture occasions only), * 'lognormal´ gives a CI based on the assumption that the estimator is normally distributed (2 capture occasions only), * 'profile´ gives a profile likelihood CI (2 capture occasions only).
nboot	number of bootstrap replications.
vlevels	vector of percentage levels for confidence intervals.
plot	if true the distribution of the group abundance estimates are plotted.
Chapmod	if TRUE, Chapman's modification of the Petersen estimator is used (2 capture occasions only)
numerical	if FALSE, an analytic estimator is used (2 capture occasions only), else the likelihood is maximized numerically
seed	Number passed to set.seed() to initialise random number generator

Details

Details of the bootstrap methods are given in Borchers et al. (2002), pp112-113.

Value

An object of class 'int.est.crM0´ containing the following items:

levels	percentage levels for confidence interval
ci	the confidence interval
boot.mean	mean of bootstrap estimates
boot.dbn	full set of nboot bootstrap estimates.
init.N	Equal to the object 'init.N' passed to the function
Chapmod	Equal to the object 'Chapmod' passed to the function
numerical	Equal to the object 'numerical' passed to the function
se	standard error
cv	coefficient of variation
ci.type	Equal to the object 'ci.type' passed to the function
parents	Details of WiSP objects passed to function
created	Creation date and time
seed	Equal to the argument 'seed' passed to the function

References

Borchers, D.L., Buckland, S.T. and Zucchini, W. 2002. Estimating animal abundance: closed populations. Springer. London. 314pp.

See Also

setpars.survey.cr, generate.sample.cr point.est.crM0

Examples

cr.reg<-generate.region(x.length=100, y.width=50)

cr.dens <- generate.density(cr.reg)
cr.poppars<-setpars.population(density.pop = cr.dens, number.groups = 100, 
                              size.method = "poisson", size.min = 1, size.max = 5,
                              size.mean = 1, exposure.method = "beta",exposure.min = 2,
                              exposure.max = 10, exposure.mean = 3, exposure.shape = 0.5,
                              type.values = c("Male","Female"), type.prob = c(0.48,0.52))
cr.pop<-generate.population(cr.poppars)

cr.des<-generate.design.cr(cr.reg, n.occ = 4)
cr.survpars<-setpars.survey.cr(cr.pop, cr.des, pmin.unmarked=0.00001, pmax.unmarked=0.5, improvement=0.01)
cr.samp<-generate.sample.cr(cr.survpars)

# M0
cr.ci.M0<-int.est.crM0(cr.samp)
summary(cr.ci.M0)
plot(cr.ci.M0)

dill/wisp documentation built on May 15, 2019, 8:31 a.m.