Where w are the weights
Description:
Data elements with a high value for the weight contribute more to the weighted mean than do elements with a low value for the weight. The weights must not be negative.
Example:
I buy 20 red balls and 30 blue balls. Red balls cost one dollar each, blue balls cost two dollars each. What is the average price of the balls I purchased?
20*1+30*2/50=80/50=$1.60
Another way using proportions: red balls represent 40%, blue balls 60%.
0.4*1+0.6*2/1=$1.60
