Each rectangle stands for a cluster, and the simple random sampling without replacement is performed for each cluster. All points in the clusters being sampled will be drawn out.
sample.cluster(pop = ceiling(10 * runif(10, 0.2, 1)), size = 3, p.col = c("blue",
"red"), p.cex = c(1, 3), ...)a vector for the size of each cluster in the population.
the number of clusters to be drawn out.
different colors / magnification rate to annotate the population and the sample
other arguments passed to rect to annotate the
``clusters''
None (invisible NULL).
Examples at https://yihui.name/animation/example/sample-cluster/
sample, sample.simple,
sample.ratio, sample.strat,
sample.system