Rcapture (version 1.1)

hare: Closed Population Data for Snowshoe Hares

Description

This data set contains closed population capture history data for snowshoe hares.

Usage

data(hare)

Details

This data set is analysed in Cormack (1989) and Agresti (1994). This data set's format is the default one, i.e. each row represents the capture history of one animal.

References

Agresti, A. (1994). Simple capture-recapture models permitting unequal catchability and variable sampling effort. Biometrics, 50, 494--500. 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/ Cormack, R. M. (1989). Log-linear models for capture-recapture. Biometrics, 45, 395--413.

Examples

data(hare)
desc<-descriptive(hare)
plot(desc)
  # The fi plot shows that the two animals caught on all occasions create 
  # some heterogeneity in the capture probabilities.

closedp(hare)
  # The best fitting model Mth Poisson2(N = 81.1, s.e.=5.7) has an AIC of 146. 

  # One can compare the fit of this model with that obtained by removing the
  # 2 hares caught 6 times. This can be done by adding a column to the design 
  # matrix for Mt taking the value 1 for the capture history (1,1,1,1,1,1).
col<-rep(0,2^6-1)
mat<-histpos.t(6)
col[apply(mat,1,sum)==6]<-1
closedp.mX(hare,mX=cbind(mat,col),mname="Mt without 111111")
  # This gives N = 76.8 (s.e.=3.9) with an AIC of 146.

  # Profile likelihood confidence intervals for both models:
profileCI(hare,m="Mth",h="Poisson",a=2)
profileCI(hare,mX=cbind(mat,col),mname="Mt without 111111")