S.SY {TeachingSampling}R Documentation

Systematic Sampling

Description

Draws a Systematyc sample of size $n$ from a population of size $N$

Usage

S.SY(N, a)

Arguments

N Population size
a Number of groups dividing the population

Details

The selected sample is drawn acording to a random start.

Value

The function returns a vector of size n. Each element of this vector indicates the unit that was selected.

Author(s)

Hugo Andrés Gutiérrez Rojas hugogutierrez@usantotomas.edu.co

References

Madow, L.H. and Madow, W.G. (1944), Onthe theory of systematic sampling. Annals of Mathematical Statistics. 15, 1-24.
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.

See Also

E.SY

Examples

############
## Example 1
############
# Vector U contains the label of a population of size N=5
U <- c("Yves", "Ken", "Erik", "Sharon", "Leslie")
# The population of size N=5 is divided in a=2 groups
# Draws a Systematic sample. 
sam <- S.SY(5,2)
sam
# The selected sample is
U[sam]
# There are only two possible samples

############
## Example 2
############
# Uses the Marco and Lucy data to draw a Systematic sample
data(Marco)
data(Lucy)

N <- dim(Marco)[1]
# The population is divided in 6 groups of size 399 or 400 
# The selected sample
sam <- S.SY(N,6)
# The information about the units in the sample is stored in an object called data
data <- Lucy[sam,]
data
dim(data)

[Package TeachingSampling version 0.7.6 Index]