Description Usage Arguments Value Note Author(s) See Also Examples
Calculates the estimated variance of the stratified estimator for abundance in a markrecapture experiment, from vectors of sample sizes and number of recaptures, with each element corresponding to each sampling stratum.
1  vstrat(n1, n2, m2, estimator = "Chapman")

n1 
Vector of individuals captured and marked in the first sample, from each stratum 
n2 
Vector of individuals captured and marked in the second sample, from each stratum 
m2 
Vector of marked individuals recaptured in the second sample, from each stratum 
estimator 
The type of estimator to use. Allowed values are

The estimated variance of the stratified estimator
It is possible that even the stratified estimate of abundance may be biased if capture probabilities differ greatly between strata. However, the bias in the stratified estimator will be much less than an estimator calculated without stratification.
This function makes the naive assumption of independence between strata. Caution is therefore recommended.
Matt Tyers
strattest, Nstrat, rstrat, sestrat, cistrat, NChapman, NPetersen, NBailey
1 
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