Stratified random sampling is a method of sampling that divides a population into smaller groups that form the basis of test samples.

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 ...

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The COVID-19 pandemic has infected over 38 million people around the world and is showing no signs of going away any time soon. Researchers worldwide are frantically working on developing an effective ...