How can you define a macro variable in SAS?

Defining a macro variable in SAS is effectively accomplished using the %LET statement. This statement allows you to assign a value to a macro variable, which can be used later in your SAS program to dynamically change code or store values for repeated use.

When you utilize %LET, you create a macro variable in the global symbol table, making it accessible throughout the SAS session or until it’s cleared or redefined. The syntax of the %LET statement is straightforward, for example, %LET variable_name = value;. This syntax allows for straightforward assignment and easy reference to variable names in subsequent code.

Utilizing other options, such as the DATA statement or ARRAY statement, is not applicable for defining macro variables. These statements serve different purposes within SAS—DATA creates data sets and ARRAY defines arrays for data manipulation. The PROC SQL procedure is also unrelated as it is primarily used for querying and manipulating data tables rather than defining macro variables.

Therefore, the %LET statement stands out as the appropriate method for defining a macro variable in SAS, making it the correct choice.