Summaries show a result applied to all data values. For example, for a numeric fields such as "Cost," the summary value might be the sum of all the costs; for a text field such as "Customer Name," the summary value might be the count of all customers. The Summary tab lets you set the default summary function for your calculated field or measure.
Calculation list: Displays allowed summary functions for your calculated field or measure. The available options depend on the data type of the calculation. Depending on your selection, you may see additional options:
Weighted Average: Displays a Weighted On drop-down list, which allows you to choose another field or measure to use as the weight for the average.