Rcapture (version 1.1)

closedp.bc: Bias Correction for Closed Population Loglinear Models

Description

This function applies a bias correction to the abundance estimations obtained by the closedp function.

Usage

closedp.bc(X, dfreq=FALSE)

## S3 method for class 'closedp.bc':
print(x, \dots)

Arguments

X

The table of the observed capture histories in one of the two accepted formats. In the default format, it has one row per unit captured in the experiment. In this case, the number of columns in the table represents the number of capture occasions in the e

dfreq

This argument specifies the format of the data matrix X. By default, it is set to FALSE, which means that X has one row per unit. If it is set to TRUE, then the matrix X contains frequencies in its last column.

x

An object, produced by the closedp.bc function, to print.

...

Further arguments passed to or from other methods.

Value

• n
  The number of captured units
• results
  A table containing, for each model, the corrected population size estimation and its standard error.

Details

The bias correction is done through frequency modifications as described in Rivest and Levesque (2001). The variances calculated with the modified frequencies are less biased than the standard ones, but they can overestimate the mean squared errors, especially when the data is sparse.

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/ Rivest, L.P. and Levesque, T. (2001). Improved log-linear model estimators of abundance in capture-recapture experiments. Canadian Journal of Statistics, 29, 555--572.

See Also

closedp

Examples

data(mvole)
period3<-mvole[,11:15]
closedp.bc(period3)