The Excel Sumx2py2 function returns the sum of the sum of squares of two supplied sets of values. I.e.
The format of the Sumx2py2 function is:
where the array arguments are two sets of numeric values, which may be supplied to the function either directly, or as one or more cells or ranges of cells containing numeric values. These two supplied arrays must be of equal length.
Note that, if any of the values supplied to the functions are nonnumeric (including cells containing text representations of numbers), these values, and the corresponding value in the other array are ignored.
Formulas:

Results:

The above spreadsheets on the right show 2 examples of the Sumx2py2 function.
The format of the functions are shown in the top spreadsheet and the resulting values are shown in the spreadsheet below.
Note that the example in cell C3 shows that the array arguments can be supplied directly to the function, as well as in the form of arrays of cells
Further information and examples of the Excel Sumx2py2 function can be found on the Microsoft Office website
If you get an error from the Excel Sumx2py2 Function, this is likely to be the #N/A error:
#N/A    Occurs if the two supplied arrays have different lengths (i.e. contain different numbers of values) 