closedp.Mtb: Closed Population Capture-Recapture Model Mtb
Description
This function fits model Mtb for closed populations in capture-recapture experiments.
Usage
closedp.Mtb(X, dfreq=FALSE)
## S3 method for class 'closedp.Mtb':
print(x, \dots)
Arguments
X
The matrix of the observed capture histories (see Rcapture-package for a description of the accepted formats).
dfreq
A logical. By default FALSE, which means that X has one row per unit. If TRUE, it indicates that the matrix X contains frequencies in its last column.
x
An object, produced by the closedp.Mtb function, to print.
...
Further arguments to be passed to print.default.
Value
nThe number of captured units
resultsA table containing the estimated population size, the standard error of estimation, the deviance, the number of degrees of freedom and the Akaike criteria.
parMtbCapture-recapture parameters estimates for model Mtb : the abundance N, $p_1$ to $p_t$, the probabilities of first capture for each capture occasion, and $c_2$ to $c_t$, the recapture probabilities for each capture occasion.
Details
The Mtb model is non-linear. It is fitted with the optim function instead of the glm fonction. Therefore, the abundance estimate can be unstable.
For the model to be identifiable, the parameters are constrained in the following way: $logit(c_i)=logit(p_i)+b$ for i in $2,\ldots,l$.
References
Baillargeon, S. and Rivest, L.P. (2007) Rcapture: Loglinear models for capture-recapture in R. Journal of Statistical Software, 19(5), http://www.jstatsoft.org/v19/i05.