Calculate a weighted average from any set of values and their weights.
A weighted average gives different values different levels of importance, unlike a simple average which treats everything equally - useful for grades, portfolio returns, or any scenario where items carry different weights.
Weighted Average = Σ(Value × Weight) ÷ Σ(Weight)
A 90 weighted 3 times and a 75 weighted once gives a weighted average of 86.25 - not the simple average of 82.5.
Sum of (value × weight) divided by sum of all weights.
It accounts for the relative importance of each value.
A course grade where exams count more than homework.