
 Encyclopedia: Weighted harmonic 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. 
  In statistics, given a set of data, X = { x1, x2,..., xn} and corresponding weights, W = { w1, w2,..., wn} the weighted geometric mean is calculated as Note that if all the weights are equal, the weighted geometric mean is the same as the geometric mean. 
  In statistics, central tendency is an average of a set of measurements, the word average being variously construed as mean, median, or other measure of location, depending on the context. 
 www.nationmaster.com /encyclopedia/Weightedharmonicmean (374 words) 
