Statistical Analysis System (SAS) Programming Certification Practice Exam

What must BY variables be in order to process BY-group analysis?

1. indexed or sorted

2. sorted only

3. indexed only

4. not required to be sorted or indexed

The correct answer is: indexed or sorted

For a BY-group analysis in SAS, the BY variables must be either indexed or sorted. This requirement ensures that the data is organized in a way that facilitates the efficient processing of separate analyses for each group defined by the BY statement. When data is sorted, SAS processes each group sequentially, following the order of the BY variables. If the data is indexed, SAS can quickly locate and access the records for each group without scanning the entire dataset, enhancing performance, especially with larger datasets. This dual requirement allows flexibility in how the data can be prepared for analysis. Sorting the data beforehand is a common practice, while indexing can be particularly useful when you have to conduct multiple analyses on the same dataset. Therefore, having the option of either sorting or indexing helps in maintaining efficiency and improving the speed of operations during BY-group processing.