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In SAS, how can I randomly select a certain number of observations from a data set?

You can use the SURVEYSELECT procedure for random sampling. The procedure supports various methods for selecting probability-based random samples from the existing data set. The SURVEYSELECT procedure can conduct simple (SRS), unrestricted (URS), systematic (SYS), and sequential (SEQ) random sampling methods. It also supports the probability-proportional-to-size (PPS) method.

Suppose you want to randomly draw 100 observations from the data set pop with 7,000 observations. Consider the following SAS code:

PROC SURVEYSELECT DATA=pop OUT=sample METHOD=SRS SAMPSIZE=100 SEED=1234567; RUN;

The METHOD=SRS option specifies the simple random sampling method. The SEED option specifies the seed to be used in the random number generation, allowing replication of the same set of random numbers. The 100 observations drawn are stored in the data set sample.

If you have questions about using statistical and mathematical software at Indiana University, email UITS Research Analytics (formerly known as the Stat/Math Center). Research Analytics is located on the IU Bloomington campus at 410 N. Park Avenue and is open for consultation by appointment Monday-Friday 9am-5pm. For more, visit Research Analytics on the web, or call 812-855-4724 (IUB) or 317-278-4740 (IUPUI).

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Last modified on April 23, 2012.

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