A data scientist uses PROC SURVEYSELECT in SAS to create a stratified random sample for model building, stratifying by a 'region' variable. Which option ensures proportional allocation across strata?
Select an answer to reveal the explanation.
Short Explanation and Infographic
Here's the deal — a is correct because PROC SURVEYSELECT uses the SAMPRATE= option in the STRATA statement (or the overall PROC statement) to specify the sampling proportion. When the same sampling rate is applied to all strata, the result is proportional allocation — each stratum contributes observations proportional to its size.
Full explanation below image
Full Explanation
A is correct because PROC SURVEYSELECT uses the SAMPRATE= option in the STRATA statement (or the overall PROC statement) to specify the sampling proportion. When the same sampling rate is applied to all strata, the result is proportional allocation — each stratum contributes observations proportional to its size. B is wrong because ALLOC=PROP is not a valid PROC SURVEYSELECT option (it is used in PROC POWER for sample allocation). C is wrong because METHOD= specifies the sampling design (SRS, systematic, etc.), not stratification allocation. D (STRATIFY=PROPORTIONAL) is not valid syntax.