Compute a simple random sample size for an estimated mean
Compute a simple random sample size using either a target coefficient of variation, CV_0, or target variance, V_0, for an estimated mean.
nCont(CV0=NULL, V0=NULL, S2=NULL, ybarU=NULL, N=Inf, CVpop=NULL)
CV0 |
target value of coefficient of variation of \bar{y_s} |
V0 |
target value of variance of \bar{y_s} |
S2 |
unit (population) variance |
ybarU |
population mean of target variable |
N |
number of units in finite population |
CVpop |
unit (population) coefficient of variation |
If CV_0 is the desired target, then the unit CV, CVpop,
or the population mean and variance, ybarU and S2, must also be provided.
If V_0 is the constrained value, then S2 must be also be included in the function call.
numeric sample size
Richard Valliant, Jill A. Dever, Frauke Kreuter
Valliant, R., Dever, J., Kreuter, F. (2013, chap. 3). Practical Tools for Designing and Weighting Survey Samples. New York: Springer.
nCont(CV0=0.05, CVpop=2)
nCont(CV0=0.05, CVpop=2, N=500)
nCont(CV0=0.10/1.645, CVpop=1)
# Compute sample size for a ratio estimator in smho98 population
# Identify large units to select with certainty first
data(smho98)
cert <- smho98[,"BEDS"] > 2000
tmp <- smho98[!cert, ]
tmp <- tmp[tmp[, "BEDS"] > 0, ]
x <- tmp[,"BEDS"]
y <- tmp[, "EXPTOTAL"]
m <- lm(y ~ 0 + x, weights = 1/x)
ybarU <- mean(y)
S2R <- sum(m$residuals^2/(length(x)-1))
nCont(CV0=0.15, S2=S2R, ybarU=ybarU)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.