The attached example workbook uses the example data set Superstore to demonstrate the following instructions:

1. Create a Parameter, 'N Parameter', setting it to Integer and the number of values you want displayed (3 in this case)

2. Create a calculated field with a name like "Top & Bottom N Filter" with a calculation similar to the following:

   RANK( SUM( [Sales] ), 'desc' ) <= [N Parameter]

   OR

   RANK( SUM( [Sales] ), 'asc' ) <= [N Parameter]

   The above calculation returns a value of true if SUM( [Sales] ) is the highest N ranking sub-categories for either largest first or smallest first.

3. Drag Top & Bottom N Filter to the Filters shelf and click OK to close the Filter dialog.

4. In the Filter dialog, check True and click OK.