Which of the following is not a part of a SAS data set?

In the context of SAS data sets, it is essential to recognize the components that make up a data set. A standard SAS data set consists of two primary sections: the descriptor portion and the data portion. The descriptor portion holds metadata about the data set, including information such as variable names, types, formats, and other attributes. The data portion contains the actual data values corresponding to the variables described in the descriptor section.

The format index portion is not a standard part of a SAS data set structure. While formats can be applied to variables to control how data is displayed or processed, the format index is a separate concept that assists in improving the performance of format lookups but does not constitute a direct component of the data set itself.

The other options, the descriptor portion and the data portion, are integral components of every SAS data set. Therefore, recognizing the format index portion as not part of a SAS data set structure is key to understanding the components that form a complete data set in SAS.