SAS Stratified Random Sample

This post was kindly contributed by AFHood Group Blog » SAS - go there to comment and to read the full post.

There are many ways to take a stratified random sample (SRS), but we find the it doesn’t always come out as expected. That was until we started using some examples we found in a paper by Diana Suhr. This is a great example of sampling with various numbers of strata.

Example #1


PROC FREQ DATA = RAWSUB;

 TABLES GEND/OUT=NEWFREQ NOPRINT; 
DATA NEWFREQ2 ERROR;

 SET NEWFREQ;

 SAMPNUM=(PERCENT * 500)/100;

 _NSIZE_= ROUND(SAMP,1);

 SAMPNUM=ROUND(SAMPNUM,.01);

 IF _NSIZE_=0 THEN OUTPUT ERROR;

 IF _NSIZE_=0 THEN DELETE;

 OUTPUT NEWFREQ2; 
DATA NEWFREQ3;

 SET NEWFREQ2;

 KEEP GEND _NSIZE_; 
PROC SORT DATA = NEWFREQ3;

 BY GEND; 
PROC SORT DATA = RAWSUB;

 BY GEND; 
PROC SURVEYSELECT DATA=RAWSUB

 OUT=SAMPFL

 SAMPSIZE=NEWFREQ3;

 STRATA GEND;

 ID ID GEND; 
PROC FREQ DATA = SAMPFL;

 TABLES GEND/OUT=SAMPFREQ NOPRINT; 
PROC PRINT DATA=SAMPFREQ;

TITLE ‘SAMPLE FREQUENCIES’; 
PROC PRINT DATA = ERROR;

TITLE 'STRATA DELETED’;

PROC DELETE DATA = NEWFREQ NEWFREQ2 NEWFREQ3 SAMPFL SAMPFREQ ERROR;

You can view the whole paper including other examples here:

http://support.sas.com/resources/papers/proceedings09/058-2009.pdf

This post was kindly contributed by AFHood Group Blog » SAS - go there to comment and to read the full post.

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