Systematic sampling
Uses the systematic method to select a sample of units (unequal probabilities, without replacement, fixed sample size).
UPsystematic(pik,eps=1e-6)
pik |
vector of the inclusion probabilities. |
eps |
the control value, by default equal to 1e-6. |
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).
Madow, W.G. (1949), On the theory of systematic sampling, II, Annals of Mathematical Statistics, 20, 333-354.
############ ## 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)
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