# Weighted average

From AMS Glossary

## weighted average

A representative value for a set of numbers

*x*_{1},*x*_{2}, · · ·,*x*_{n}given by the sum*w*_{1}*x*_{1}+*w*_{2}*x*_{2}+ · · · +*w*_{n}*x*_{n}, where the numbers*w*_{i}are the weights.The weights are usually assigned positive values that sum to unity. If all the weights are equal, the weighted mean reduces to the arithmetic mean.