SS.est: Sightability estimate with variance components estimator from...

Description Usage Arguments Value Author(s) References See Also

View source: R/SS.est.R

Description

Estimates population size, with variance estimated using Steinhorst and Samuel (1989) and Samuel et al.'s (1992) estimator. Usually, this function will be called by Sight.Est

Usage

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SS.est(
  total,
  srates,
  nh,
  Nh,
  stratum,
  subunit,
  covars,
  beta,
  varbeta,
  smat = NULL
)

Arguments

total

Number of animals in each independently sighted group

srates

Plot-level sampling probability

nh

Number of sample plots in each stratum

Nh

Number of population plots in each stratum

stratum

Stratum identifiers (associated with the independently observed animal groups)

subunit

Plot ID (associated with the independently observed animal groups)

covars

Matrix of sightability covariates (associated with the independently observed animal groups)

beta

Logistic regression parameter estimates (from fitted sightability model)

varbeta

Estimated variance-covariance matrix for the logistic regression parameter estimates (from fitted sightability model)

smat

Estimated variance-covariance matrix for the inflation factors (1/probability of detection). This is an n.animal x n.animal matrix, and is usually calculated within the SS.est function. Non-null values can be passed to the function (e.g., if a bootstrap is used to estimate uncertainty due to the estimated detection parameters).

Value

tau.hat

Sightability estimate of population size, tau^

VarTot

Estimated variance of tau^

VarSamp

Estimated variance component due to sampling aerial units

VarSight

Estimated variance component due to sighting process (i.e., series of binomial rv for each animal group)

VarMod

Estimated variance component due to estimating detection probabilities using test trial data

Author(s)

John Fieberg

References

Steinhorst, R. K., and M.D. Samuel. 1989. Sightability adjustment methods for aerial surveys of wildlife populations. Biometrics 45:415-425.

Wong, C. 1996. Population size estimation using the modified Horvitz-Thompson estimator with estimated sighting probabilities. Dissertation, Colorado State University, Fort Collins, USA.

See Also

Sight.Est, Wong.est


SightabilityModel documentation built on Oct. 7, 2021, 1:07 a.m.