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
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## 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]
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## 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)