epi.cluster1size {epiR} | R Documentation |
Returns the required number of clusters to be sampled using a one-stage cluster sampling strategy.
epi.cluster1size(n, mean, var, epsilon, method = "mean", conf.level = 0.95)
n |
integer, representing the total number of clusters in the population. |
mean |
number, representing the population mean of the variable of interest. |
var |
number, representing the population variance of the variable of interest. |
epsilon |
the maximum relative difference between our estimate and the unknown population value. |
method |
a character string indicating the method to be used. Options are total , mean or mean.per.unit . |
conf.level |
scalar, defining the level of confidence in the computed result. |
Returns an integer defining the required number of clusters to be sampled.
Levy PS, Lemeshow S (1999). Sampling of Populations Methods and Applications. Wiley Series in Probability and Statistics, London, pp. 258.
## We intend to conduct a survey of residents to estimate the total number ## over 65 years of age that require the services of a nurse. There are ## five housing complexes in the study area and we expect that there might ## be a total of around 34 residents meeting this criteria (variance 6.8). ## We would like the estimated sample size to provide us with an estimate ## that is within 10% of the true value. How many housing complexes (clusters) ## should be sampled? epi.cluster1size(n = 5, mean = 34, var = 6.8, epsilon = 0.10, method = "total", conf.level = 0.999) ## We would need to sample 3 housing complexes to meet the specifications ## for this study.