What is the difference between representative samples and random samples, and how are they are used to reduce sampling bias?

A simple random sample is used to represent the entire data population. A stratified random sample divides the population into smaller groups based on shared characteristics.

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 ...

However, at about that same time, the first efforts were made to develop alternative non-random quota sampling methods. Quota samples are non-probability samples that are controlled to be distributed ...

For example, if you were carrying out research about the catering facilities in your school, a random sample would mean every person in the school would have an equal chance of being selected.

Systematic Random Sampling The method of systematic random sampling (METHOD=SYS) selects units at a fixed interval throughout the sampling frame or stratum after a random start. PROC SURVEYSELECT ...