DAVERAGE

Database Functions:
Function: DAVERAGE() - Returns the average of selected database entries that match criteria.
Database

     +--------+--------+-----+-------+--------+
     | A      | B      | C   | D     | E      |
+----+--------+--------+-----+-------+--------+
|  4 | Tree   | Height | Age | Yield | Profit |
|  5 | Apple  | 18     | 20  | 14    | 105    |
|  6 | Pear   | 12     | 12  | 10    | 96     |
|  7 | Cherry | 13     | 14  | 9     | 105    |
|  8 | Apple  | 14     | 15  | 10    | 75     |
|  9 | Pear   | 9      | 8   | 8     | 76.8   |
| 10 | Apple  | 8      | 9   | 6     | 45     |
+----+--------+--------+-----+-------+--------+

Criteria

    +--------+--------+
    | A      | B      |
+---+--------+--------+
| 1 | Tree   | Height |
| 2 | =Apple | >10    |
+---+--------+--------+

The Average yield of Apple trees over 10' in height
=DAVERAGE(A4:E10,"Yield",A1:B2)
DAVERAGE() Result is 12
Criteria

    +--------+
    | A      |
+---+--------+
| 1 | Tree   |
| 2 | =Apple |
| 3 | =Pear  |
+---+--------+

The Average age of all Apple and Pear trees in the orchard
=DAVERAGE(A4:E10,3,A1:A3)
DAVERAGE() Result is 12.8