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 a subset of a statistical population where each member of the population is equally likely to be chosen.

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.

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 ...

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 ...

The author presents a generalization he worked out in 1950 of von Neumann's method of generating random samples from the exponential distribution by comparisons of uniform random numbers on $(0, 1)$.

A comparison of the three sampling methods shows that stratified random sampling is an efficient method that guarantees a sample which is proportional to the extension of the environmental types. We ...