Rows in the data set are called observations, and columns are called variables. Missing values do not affect the structure of the data set.

When it encounters a DATA, PROC, or RUN statement, SAS stops reading statements and executes the previous step in the program. This program contains one DATA step and two PROC steps, for a total of three program steps.

It must be a character variable, because the values contain letters and underscores, which are not valid characters for numeric values.

It must be a numeric variable, because the missing value is indicated by a period rather than by a blank.

Variable names follow the same rules as SAS data set names. They can be 1 to 32 characters long, must begin with a letter (A-Z, either uppercase or lowercase) or an underscore, and can continue with any combination of numbers, letters, or underscores.

To store a file permanently in a SAS data library, you assign it a libref other than the default Work. For example, by assigning the libref Profits to a SAS data library, you specify that files within the library are to be stored until you delete them. Therefore, SAS files in the Sashelp, Sasuser, and Profits libraries are permanent files.

To reference a temporary SAS file in a DATA step or PROC step, you can specify the one-level name of the file (for example, Forecast) or the two-level name using the libref Work (for example, Work.Forecast).

The numeric variable Balance has a default length of 8. Numeric values (no matter how many digits they contain) are stored in 8 bytes of storage unless you specify a different length.

The five statements are 1) the PROC PRINT statement (two lines long); 2) the VAR statement; 3) the WHERE statement (on the same line as the VAR statement); 4) the LABEL statement; and 5) the RUN statement (on the same line as the LABEL statement).

Every SAS file is stored in a SAS library, which is a collection of SAS files, such as SAS data sets and catalogs. In some operating environments, a SAS library is a physical collection of files. In others, the files are only logically related. In the Windows and UNIX environments, a SAS library is typically a group of SAS files in the same folder or directory.