FACTOID # 145: Three of the top ten countries for GDP per capita are island nations: Bermuda, Cayman Islands, and Iceland.
 
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Encyclopedia > Weighted arithmetic mean

In statistics, given a set of data,

X = { x1, x2, ..., xn}

and corresponding weights,

W = { w1, w2, ..., wn}

the weighted mean is calculated as

Note that if all the weights are equal, the weighted mean is the same as the arithmetic mean. While weighted means generally behave in a similar fashion to arithmetic means, they do have a few counter-intuitive properties, as captured for instance in Simpson's paradox.


Weighted versions of other means can also be calculated. Examples of such weighted means include the weighted geometric mean and the weighted harmonic mean.


See also

average, summary statistics, central tendency


  Results from FactBites:
 
Average - Wikipedia, the free encyclopedia (595 words)
Arithmetic mean - the sum of all measurements divided by the number of observations in the data set
Weighted mean - an arithmetic mean that incorporates weighting to certain data elements
The only significant reason why the arithmetic mean (classical average) is generally used in scientific papers is that there are various (statistical) tests which can be applied to test the statistical significance of the results, as well as the correlations that are explored through these metrics.
  More results at FactBites »


 

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