CalculateSimpleSampleSize {capm}

Simple random sample size

Description

Calculates sample size to estimate a total from a simple sampling design.

Usage

CalculateSimpleSampleSize(x = NULL, N = NULL, conf.level = 0.95,
  error = 0.1)

Arguments

x

vector with variable collected in a pilot and to be estimated. If x is a scalar, it is used as the relative variance of the variable to be estimated (((N - 1) / N * sd(x)^2) / mean(x)^2).

N

numeric indicating the number of sampling units in the population.

conf.level

the confidence level required. It must be numeric between 0 and 1 inclusive.

error

the maximum relative difference between the estimate and the unknown population value. It must be numeric between 0 and 1 inclusive.

Value

numeric sample size rounded up to nearest integer.

References

Levy P and Lemeshow S (2008). Sampling of populations: methods and applications, Fourth edition. John Wiley and Sons, Inc.

http://oswaldosantos.github.io/capm

Examples

# Using a pilot sample from a population with 10000 sampling units.
pilot <- rpois(50, 0.8)
CalculateSimpleSampleSize(x = pilot, N = 10000,
                          conf.level = 0.95, error = 0.1)

# Using expected mean and standard deviation for a population
# with 10000 sampling units.
mean_x <- mean(pilot)
sd_x <- sd(pilot)
N <- 10000
V <- ((N - 1) / N * sd_x^2) / mean_x^2
CalculateSimpleSampleSize(x = V, N = 10000, conf.level = 0.95, error = 0.1)