Function Weighted_Average(optional x(), optional w())
dim WA as double
dim SUMWX as double
dim SUM as double
For i = 1 to UBound(x)
SUMWX = SUMWX + w(i,1)*x(i,1)
Next i
For b = 1 to UBound(x)
SUM = SUM + w(i,1)
Next b
WA = SUMWX/SUM
Weighted_Average = WA
End Function