I have a custom report in ArcGIS that summarizes my fields using basic descriptive statistics. For example, here is a summary field that calculates the maximum value in the group for a particular field:

What I would like to do is calculate the range (|max-min|). However, this function is not included in the summary statistics. I think that I can use the "Fields>Calculated" menu to add custom fields. Here is a screenshot of that:

Does anyone have an idea of what has to go in as the "Formula" for the field calculation, and how do I fill out the element properties for the field I would like to populate with this calculation:
