If the AVERAGE function is applied in the filtered data or list, it will not get the correct average. In this condition, the SUBTOTAL function can help you average filtered data/list in Excel. Supposing you have filtered your table as following screen shots shown, you can get its average as follows:
In a blank cell enter the formula =SUBTOTAL(1,C12:C24) (C12:C24 is the range with all filtered data in Amount column) and press the Enter key.
Sum/Count/Average visible cells only in a specified range with ignoring hidden or filtered cells/rows/columns
The normally SUM/Count/Average function will count all cells in the specified range on matter cells are hidden/filtered or not. While the Subtotal function can only sum/count/average with ignoring hidden rows. However, Kutools for Excel SUMVISIBLE/COUNTVISIBLE/AVERAGEVISIBLE functions will easily calculate the specified range with ignoring any hidden cells, rows, or columns.