Apple Numbers '08 - Manual (Page 211)

Chapter 12 Dictionary of Functions 211
AVERAGE
The AVERAGE function calculates the average (arithmetic mean) of a set of numbers.
AVERAGE(number, [number, . . .])
 number: One or more numbers, numeric expressions, or references to cells
containing numbers or numeric expressions.
Notes
To calculate the average, AVERAGE divides the sum of the numbers by the number of
numbers.
Table cells containing text values or Boolean values (TRUE or FALSE) are ignored. Text
values included as arguments result in an error. Referenced text is ignored with no
warning.
AVERAGEA
The AVERAGEA function calculates the average (arithmetic mean) of a set of values,
including text and Boolean values.
AVERAGEA(value, [value, . . .])
 value: One or more numeric or Boolean values or references to cells containing
numeric, textual, or Boolean values.
Notes
Unlike the AVERAGE function, which ignores cells that don’t contain numbers,
AVERAGEA assigns a value of 0 to any text value, 0 to the Boolean value FALSE, and 1 to
the Boolean value TRUE and includes those values in the computation.
For a data set containing only numbers, AVERAGEA returns the same result as AVERAGE.
Examples
AVEDEV(2,2,2,4,4,4) returns 1.
AVEDEV(2,2,2,2,3,3,3,3,4,4,4,4) returns 0.6666667.
Examples
AVERAGE(4,4,4,6,6,6) returns 5.
AVERAGE(2,2,2,2,3,3,3,3,4,4,4,4) returns 3.