Final answer:
The default field setting in the Values area calculates the sum of items, categorized by Row Labels or Column Labels. It's crucial to label columns as 'Quantity/units' to clarify the calculations and unitless numbers presented.
Step-by-step explanation:
The default field setting in the Values area is to calculate a sum of the items in this drop area by the categories in the Row Labels area or Column Labels area. When designing a table or graph, it is essential to label columns or axes clearly. For instance, a column might be labeled in the format of Quantity/units, indicating the units that the quantity should be divided by to obtain a unitless number. This is particularly true for pivot tables or data summaries in spreadsheet programs, where the Values area can perform various calculations such as sum, average, or count, depending on the data and the user's needs. The labels help in understanding the data representation and making accurate interpretations of the data visualizations.