Consider a population in which the variable of interest tends to be at or near zero for many of the population units but a subgroup exhibits values distinctly different from zero. Such a population ...

Consider the example in the section "Stratified Sampling". The study population is a junior high school with a total of 4,000 students in grades 7, 8, and 9. Researchers want to know how much these ...

PROC SURVEYSELECT provides a variety of methods for selecting probability-based random samples. With probability sampling, each unit in the survey population has a known, positive probablity of ...

The random sample survey is a commonly used method in market research and such surveys generally are considered to provide more robust results than purposive or convenience (such as quota) samples.