Which statement allows for maintaining total counts across observations in SAS?

The statement that allows for maintaining total counts across observations in SAS is RETAIN. This statement is crucial when you want to preserve the value of a variable from one iteration of the DATA step to the next. By default, SAS resets the value of variables to missing at the beginning of each iteration. The RETAIN statement prevents this reset, enabling the accumulation of values, such as total counts.

For instance, if you are counting the number of occurrences or summarizing data across multiple observations, using the RETAIN statement will let you keep a running total as you loop through the dataset. You can initialize a counter variable and use RETAIN to ensure that its value carries over as new observations are processed, resulting in an accurate cumulative tally.

On the other hand, while SUM and COUNT are useful functions for aggregating values, they do not inherently maintain state across observations like RETAIN does. ACCUMULATE is not a valid SAS statement and thus cannot be used for this purpose in the context of maintaining totals.