Numeric - WeightedMean

Syntax:
=WeightedMean(Numbers, Weights)

Description:
Calculates the weighted mean of the numbers.

When the weights are all 1 (or otherwise equal) the weighted mean is equal to the unweighted average. The weighted mean is the sum over i of Numbers(i) * Weights(i) devided by the sum of all the weights.

The weights cannot 0 or negative.

Numbers: Cell range where the numbers are stored.
Weights: Cell range where the weights are stored.

Example:
=WeightedMean(A1:A10, B1:B10)