The problem of estimating the variance of the ratio estimator in sampling with probability proportional to aggregate size is investigated. The form of nonnegative unbiased variance estimators is found ...

Sampling is a tool researchers use for marketing, sociology or empirical study. In order for sampling to be productive, the data analysis must not be tainted. There are techniques for creating a ...

A practical method of drawing sampling units with probabilities exactly proportional to size is described, in which both preliminary calculations and the addition of a large number of sizes are ...