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Weighted Mean


The weighted mean, also called the weighted arithmetic mean, of a discrete set of numbers {x_1,x_2,...,x_n} with weights {w_1,w_2,...,w_n} is given by

 <x>=sum_(i=1)^nw_ix_i,
(1)

where each weight w_i is a nonnegative real number and

 sum_(i=1)^nw_i=1.
(2)

For a function x(t) on a set T and a nonnegative function w(t) on T satisfying

 int_Tw(t)dt=1,
(3)

the weighted mean of x is given by

 <x>=int_Tw(t)x(t)dt.
(4)

Weighted means have many applications in physics, including finding the center of mass and moments of inertia of an object with a known density distribution and computing electric and magnetic multipole moments of charge and current distributions, respectively.

Weighted means are also commonly used in statistics, for instance, in population studies.


See also

Arithmetic Mean, Mean

This entry contributed by David Terr

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Cite this as:

Weisstein, Eric W., with contributions by David Terr. "Weighted Mean." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/WeightedMean.html

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