Weightaverage
Weight average, or weighted mean, is a measure of central tendency that assigns different importance to observations through weights. If x1,...,xn are values and w1,...,wn are weights, the weighted average is sum(wi xi) / sum(wi). When weights sum to 1, the denominator is 1 and the expression reduces to sum(wi xi).
Weights are typically nonnegative and reflect frequency, reliability, or importance; negative weights are uncommon and can
Example: values 95, 85, 75 with weights 0.5, 0.3, 0.2 yield a weighted average of 88 (95*0.5
Applications span grading schemes, index construction, sensor fusion, and data analysis where observations differ in relevance;
Computation in practice: form the sum of products and divide by the sum of weights. In software,