sampling (version 2.9)

UPsystematic: Systematic sampling

Description

Uses the systematic method to select a sample of units (unequal probabilities, without replacement, fixed sample size).

Usage

UPsystematic(pik,eps=1e-6)

Arguments

pik

vector of the inclusion probabilities.

eps

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

Value

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).

References

Madow, W.G. (1949), On the theory of systematic sampling, II, Annals of Mathematical Statistics, 20, 333-354.

See Also

inclusionprobabilities, UPrandomsystematic

Examples

# NOT RUN {
############
## 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=UPsystematic(pik)
#the sample is
(1:length(pik))[s==1]
############
## Example 2
############
data(belgianmunicipalities)
Tot=belgianmunicipalities$Tot04
name=belgianmunicipalities$Commune
pik=inclusionprobabilities(Tot,200)
#selects a sample
s=UPsystematic(pik)  
#the sample is
as.vector(name[s==1])
# extracts the observed data
getdata(belgianmunicipalities,s)
# }