When we understand the advantages and disadvantages of commonly used sampling methods (e.g., systematic sampling, simple random sampling, convenience sampling), not only do we become better ...

The stratified random sample is always at least as accurate on the average as the random sample and its relative efficiency is a monotone increasing function of the size of the sample. No general ...

Stratified Sampling with Control Sorting The next sample design for the customer satisfaction survey uses stratification by State. The sampling frame is also sorted by Type and Usage before sample ...

PPS Systematic Sampling If you specify the option METHOD=PPS_SYS, PROC SURVEYSELECT selects units by systematic random sampling with probability proportional to size. Systematic sampling selects units ...

Key fact Most sampling is random, but systematic sampling can be used if there is a trend or pattern across the habitat, such as distance up a beach, or altitude on a hillside.

A flexible sampling model is outlined for use in a spatial context. The new method is designed to distribute the available samples in such a way that areas of greatest vegetational heterogeneity are ...