Related Function:
The DEVSQ function returns the sum of squares of deviations of data points from their sample mean.
Syntax
=DEVSQ(num_1,[num_2] … )
Note: Beginning with Excel 2007, you can enter up to 255 number arguments to the function. Excel 2003 would only accept up to 30 number arguments.
Arguments
Argument  Description 

num_1  The first number, cell reference, or range for which you want the average 
[num_2], …  Optional. Additional numbers, cell references or ranges for which you want the average, up to a maximum of 255 
Examples
A  B  C  D  E  

1  Data  Formula  Result  Notes  
2  16  =DEVSQ(A2:A)  29.2  Sum of squares of deviations of data from their sample mean  
3  12  
4  17  
5  11  
6  12 
Common Function Error(s)
Problem  What went wrong  

#VALUE!  Occurs if any of the supplied values are text values that cannot be interpreted as numeric  
#NUM!  Occurs if none of the values supplied to the function are numeric

The equation for the sum of squared deviation is: