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 new sampling scheme, with probability of inclusion proportional to size, is proposed for a sample of given size n. It satisfies many requirements of a good sampling scheme under conditions usually ...