Definition Weighted average

A weighted average is a special type of average, in which observations are scaled according to varying degrees of importance.

To take an example, let's imagine that a student at the university has so far taken three exams. In the first exam, she had a score of 8/10, in the second, a score of 10/10, and in the third, a score of 6/10. The simple average of her scores is then 8/10. However, these exams, when passed, granted a different number of credit points. The first and second granted 10 credit points each, but the third only granted 3 credit points. In this case, it makes sense to calculate a weighted average that also accounts for the fact that the third exam granted fewer credit points to the student. This weighted average is calculated by summing up the scores of the exams multiplied by their respective weights, and then divide them by the sum of the weights. In this example (8x10 + 10x10 + 6x3)/(10+10+3) = 8.6/10.