Returns the average of the absolute deviations of data points from their mean. AVEDEV is a measure of the variability in a data set.
Syntax
AVEDEV(number1,number2, ...)
Number1, number2, ... are 1 to 30 arguments for which you want the average of the absolute deviations.
Remarks

The arguments must be either numbers or column references that contain numbers.

If a column reference argument contains text, logical values, or is empty, those values are either ignored or return the #VALUE! error value; however, the value zero is included.

The equation for average deviation is:
AVEDEV is influenced by the unit of measurement in the input data.
Example
Col1 
Col2 
Col3 
Col4 
Col5 
Col6 
Col7 
Formula 
Description (Result) 
4 
5 
6 
7 
5 
4 
3 
=AVEDEV([Col1],[Col2],[Col3],[Col4],[Col5],[Col6],[Col7]) 
Average of the absolute deviations of the numbers from their mean (1.020408) 