How can you use the OUTPUT statement in SAS?

The OUTPUT statement in SAS is specifically used to write selected observations to a dataset. When you include this statement within a DATA step, you can control which observations are output to the new dataset created by the DATA step. This provides flexibility in terms of data manipulation, allowing you to write only those observations that meet certain criteria or conditions.

For instance, if you have conditional logic in your DATA step and only want to retain observations that satisfy specific conditions, you can use the OUTPUT statement to specify exactly which observations should be transferred to the resulting dataset. This capability is essential for creating refined datasets that focus on relevant subsets of your data.

In contrast, the other choices involve actions that are not associated with the OUTPUT statement. Displaying results in the SAS log pertains to the PUT statement or various PROC steps, declaring new variables typically involves using assignment statements, and merging datasets is achieved through the MERGE statement, not the OUTPUT statement.