In the Aggregate Attributes window, do any of the following:
To use only the selected records in the operation, enable the Aggregate selected shapes only check box.
To compute the results based on the shapes that contain the same style in the Representation Editor, enable the Representation values option and select an attribute and function that you want to use.
To compute the results based on the records that contain the same attribute values, enable the Attributes option and enable the chck box next to the attribute in the Based On column. Add any function or statistic fields to the output Attribute Manager. For more information, see Adding function fields to output layers.
To add a field containing the number of records used in the calculation, enable the Add a count field check box.