What symbol represents a missing numeric variable in SAS?

In SAS, a missing numeric variable is represented by a period (.). When you encounter a numeric variable that has no value assigned to it, SAS specifically uses the period to denote that the value is missing. This is an important aspect of data management, as it allows analysts to distinguish between actual values and those that are absent.

Understanding how SAS represents missing values is crucial for accurate data analysis and reporting. For instance, when you perform calculations or statistical analyses, missing values are treated differently than zeros, making it vital to interpret data correctly.

The other symbols mentioned do not represent missing values in SAS. While NaN (Not a Number) might be used in other programming contexts to signify undefined or unrepresentable numerical values, it does not apply in SAS. The underscore is often used in other programming languages or contexts but has a different meaning in SAS. Similarly, NULL is typically associated with database systems and SQL rather than being representative of a missing numeric value in SAS.