S.STPPS {TeachingSampling} | R Documentation |
Draws a probability proportional to size simple random sample with replacement of size m_h in stratum h of size N_h
S.STPPS(S,x,mh)
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 |
The selected sample is drawn acording to the cumulative total method (sequential-list procedure) in each stratum
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
Hugo Andrés Gutiérrez Rojas hugogutierrez@usantotomas.edu.co
Sarndal, C-E. and Swensson, B. and Wretman, J. (1992), Model Assisted Survey Sampling. Springer.
Guti'errez, H. A. (2009), Estrategias de muestreo: Dise~no de encuestas y estimaci'on de par'ametros.
Editorial Universidad Santo Tom'as.
############ ## 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 Marco and Lucy data to draw a stratified random sample # according to a PPS design in each stratum data(Marco) data(Lucy) attach(Lucy) # Level is the stratifying variable summary(Level) # Defines the sample size at each stratum m1<-14 m2<-123 m3<-263 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