How can aggregation functions be utilized in calculated fields in Tableau?

Utilizing aggregation functions in calculated fields in Tableau is primarily accomplished through built-in functions like SUM(), AVG(), and COUNT(). These functions allow users to perform calculations on data at different levels of granularity. For example, using SUM() can help calculate the total sales figure, AVG() can determine the average sales amount, and COUNT() can tally the number of records that meet certain criteria.

Aggregation is essential in data visualization because it enables analysts to summarize large datasets into digestible and interpretable insights. When creating calculated fields, these aggregate functions can be employed to dynamically compute values based on the current context of the data, such as filters, groups, or date ranges, enhancing the analysis and presentation of data trends effectively.

The other methods listed do not align with the way Tableau is designed to operate. External data sources, while potentially useful, do not inherently provide aggregation capabilities within calculated fields. Coding with JavaScript is outside of Tableau’s standard functionalities for creating calculations, and exporting data to Excel removes the analysis from Tableau's interactive environment, preventing the direct use of Tableau’s powerful aggregation features.