nProp {PracTools}

Compute simple random sample size for estimating a proportion

Description

Compute the simple random sample size for estimating a proportion based on different precision requirements.

Usage

nProp(CV0 = NULL, V0 = NULL, pU = NULL, N = Inf)

Arguments

CV0

target value of coefficient of variation of the estimated proportion

V0

target value of variance of the estimated proportion

pU

population proportion

N

number of units in finite population

Details

The precision requirement of p_s can be set based on either a target coefficient of variation, CV_0, or a target variance, V_0. In either case, a value of p_U must be supplied.

Value

numeric sample size

Author(s)

Richard Valliant, Jill A. Dever, Frauke Kreuter

References

Valliant, R., Dever, J., Kreuter, F. (2018, chap. 3). Practical Tools for Designing and Weighting Survey Samples, 2nd edition. New York: Springer.

See Also

nCont, nLogOdds, nPropMoe, nWilson

Examples

# srs sample size so that CV of estimated proportion is 0.05
# assuming the population is large and pU=0.01
# Both examples below are equivalent
nProp(V0=0.0005^2, N=Inf, pU=0.01) #or
nProp(CV0=0.05, N=Inf, pU=0.01)

# srswor sample size so that half-width of 2-sided 95% CI is 0.005
nProp(V0=(0.005/1.96)^2, N=Inf, pU=0.01)