Hajekstrata {sampling}

The Hajek estimator for a stratified design

Description

Computes the Hájek estimator of the population total or population mean for a stratified design.

Usage

Hajekstrata(y,pik,strata,N=NULL,type=c("total","mean"),description=FALSE)

Arguments

y

vector of the variable of interest; its length is equal to n, the sample size.

pik

vector of the first-order inclusion probabilities for the sampled units; its length is equal to n, the sample size.

strata

vector of size n, with elements indicating the unit stratum.

N

vector of population sizes of strata; N is only used for the total estimator; for the mean estimator its value is NULL.

type

the estimator type: total or mean.

description

if TRUE, the estimator is printed for each stratum; by default, FALSE.

See Also

HTstrata

Examples

# Swiss municipalities data 
data(swissmunicipalities)
# the variable 'REG' has 7 categories in the population 
# it is used as stratification variable
# computes the population stratum sizes
table(swissmunicipalities$REG)
# do not run
#  1   2   3   4   5   6   7
# 589 913 321 171 471 186 245
# the sample stratum sizes are given by size=c(30,20,45,15,20,11,44)
# the method is simple random sampling without replacement 
# (equal probability, without replacement)
st=strata(swissmunicipalities,stratanames=c("REG"),size=c(30,20,45,15,20,11,44), 
method="srswor")
# extracts the observed data
# the order of the columns is different from the order in the swsissmunicipalities data
x=getdata(swissmunicipalities, st)
# computes the population sizes of strata
N=table(swissmunicipalities$REG)
N=N[unique(x$REG)]
#the strata 1   2   3   4   5   6   7
#corresponds to REG  4   1   3   2   5   6   7 
# computes the Hajek estimator of the total of Pop020 
Hajekstrata(x$Pop020,x$Prob,x$Stratum,N,type="total",description=TRUE)