Which function allows a Data Analyst to average sales at a less-granular level of detail than is present in the view?

The correct answer is the EXCLUDE function. This function is specifically designed to adjust the level of detail in a Tableau visualization. By using EXCLUDE, a data analyst can remove certain dimensions from the level of detail, which allows for the aggregation of data at a higher level than what is currently displayed in the view.

For instance, if a visualization shows sales data broken down by month and product category, applying the EXCLUDE function to remove the product category dimension would enable the analyst to calculate an average sales figure across all categories for each month, providing a less-granular view of the sales data.

In contrast, the other functions mentioned serve different purposes. The INCLUDE function would add dimensions to the existing level of detail, thus providing a more granular view. The SUM function calculates total sales, which does not help in reducing the level of detail. The AVERAGE function, while it does compute an average, does not have the functionality to adjust the granularity of the data being viewed in the manner that EXCLUDE does.