fbs | R Documentation |
This function implements the method proposed by Hasler and Tillé (2014). It should be used for selecting a sample from highly stratified population.
fbs(X, strata, pik)
X |
A matrix of size (N x p) of auxiliary variables on which the sample must be balanced. |
strata |
A vector of integers that specifies the stratification. |
pik |
A vector of inclusion probabilities. |
Firstly a flight phase is performed on each strata. Secondly, several flight phases are applied by adding one by one the stratum. By doing this, some strata are managed on-the-fly. Finally, a landing phase is applied by suppression of the variables. If the number of element selected in each stratum is not equal to an integer, the function can be very time-consuming.
A vector with elements equal to 0 or 1. The value 1 indicates that the unit is selected while the value 0 is for rejected units.
Raphaël Jauslin raphael.jauslin@unine.ch
Hasler, C. and Tillé Y. (2014). Fast balanced sampling for highly stratified population. Computational Statistics and Data Analysis, 74, 81-94
N <- 100 n <- 10 x1 <- rgamma(N,4,25) x2 <- rgamma(N,4,25) strata <- rep(1:n,each = N/n) pik <- rep(n/N,N) X <- as.matrix(cbind(matrix(c(x1,x2),ncol = 2))) s <- fbs(X,strata,pik) t(X/pik)%*%s t(X/pik)%*%pik Xcat <- disj(strata) t(Xcat)%*%s t(Xcat)%*%pik
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