Editing Weighted arithmetic mean (section)

=== Convex combination example ===
Since only the ''relative'' weights are relevant, any weighted mean can be expressed using coefficients that sum to one. Such a linear combination is called a [[convex combination]].

Using the previous example, we would get the following weights:
:<math>\frac{20}{20 + 30} = 0.4</math>

:<math>\frac{30}{20 + 30} = 0.6</math>

Then, apply the weights like this:
:<math>\bar{x} = (0.4\times80) + (0.6\times90) = 86.</math>