S.STPPS {TeachingSampling}

Stratified Sampling Applying PPS Design in all Strata

Description

Draws a probability proportional to size simple random sample with replacement of size m_h in stratum h of size N_h

Usage

S.STPPS(S,x,mh)

Arguments

S

Vector identifying the membership to the strata of each unit in the population

x

Vector of auxiliary information for each unit in the population

mh

Vector of sample size in each stratum

Details

The selected sample is drawn according to the cumulative total method (sequential-list procedure) in each stratum

Value

The function returns a matrix of m=m_1+\cdots+m_h rows and two columns. Each element of the first column indicates the unit that was selected. Each element of the second column indicates the selection probability of this unit

Author(s)

Hugo Andres Gutierrez Rojas [e-mail]

References

Sarndal, C-E. and Swensson, B. and Wretman, J. (1992), Model Assisted Survey Sampling. Springer.
Gutierrez, H. A. (2009), Estrategias de muestreo: Diseno de encuestas y estimacion de parametros. Editorial Universidad Santo Tomas.

See Also

E.STPPS

Examples

############
## Example 1
############
# Vector U contains the label of a population of size N=5
U <- c("Yves", "Ken", "Erik", "Sharon", "Leslie")
# The auxiliary information
x <- c(52, 60, 75, 100, 50)
# Vector Strata contains an indicator variable of stratum membership 
Strata <- c("A", "A", "A", "B", "B")
# Then sample size in each stratum
mh <- c(2,2)
# Draws a stratified PPS sample with replacement of size n=4
res <- S.STPPS(Strata, x, mh)
# The selected sample
sam <- res[,1]
U[sam]
# The selection probability of each unit selected to be in the sample
pk <- res[,2]
pk

############
## Example 2
############
# Uses the Lucy data to draw a stratified random sample 
# according to a PPS design in each stratum

data(Lucy)
attach(Lucy)
# Level is the stratifying variable
summary(Level)
# Defines the sample size at each stratum
m1<-70
m2<-100
m3<-200
mh<-c(m1,m2,m3)
# Draws a stratified sample
res<-S.STPPS(Level, Income, mh)
# The selected sample
sam<-res[,1]
# The information about the units in the sample is stored in an object called data
data <- Lucy[sam,]
data
dim(data)
# The selection probability of each unit selected in the sample
pk <- res[,2]
pk