sampling (version 2.1)

UPtille: Till� sampling

Description

Uses the Till�'s method to select a sample of units (unequal probabilities, without replacement, fixed sample size).

Usage

UPtille(pik,eps=1e-6)

Arguments

pik

the vector of the prescribed inclusion probabilities.

eps

the control value, by default equal to 1e-6.

encoding

latin1

Details

Returns a vector (with elements 0 and 1) of size N, the population size. Each element k of this vector indicates the status of unit k (1, unit k is selected in the sample; 0, otherwise). The value eps is used to control pik (pik>eps & pik < 1-eps).

References

Till�, Y. (1996), An elimination procedure of unequal probability sampling without replacement, Biometrika, 83:238-241. Deville, J.-C. and Till�, Y. (1998), Unequal probability sampling without replacement through a splitting method, Biometrika, 85:89-101.

See Also

UPsystematic

Examples

############
## Example 1
############
#defines the prescribed inclusion probabilities
pik=c(0.2,0.7,0.8,0.5,0.4,0.4)
#selects a sample
s=UPtille(pik)
#the sample is
(1:length(pik))[s==1]
############
## Example 2
############
# see the vignette (UPexamples.pdf)