How to Calculate Averages in Microsoft Access
In database applications queries are commonly used to quickly get the average of a field in a database table. Queries are used to retrieve information from your table and can also do some heavy lifting such as data transformations or calculations. In a query you can use the "Avg" function to calculate the arithmetic mean of a set of values in a specific field.
Click the "Create" tab and click "Query Design" to display the Show Table dialog window. Click the table you want to use to calculate an average and click "Add."
Double-click the field you want to use and click the "Totals" icon. Next to "Total:" in the quick table at the bottom of your computer screen select "Avg" to average the field.
Click the "View" icon to view the average result.