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 chooses the first unit randomly ...

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 at a fixed interval ...

The effect of added sugar on health is a topical area of research ... method to easily distinguish between added sugars and naturally occurring sugars in foods. This study aimed to develop a ...