How do you calculate a weighted average?
Weighted Average is the arithmetic mean of a set of data, in which some elements are considered important than the other elements. It can also be termed as the Weighted Mean. If the weights of the elements are same, then the weighted mean is the arithmetic mean.
Formula for Weighted Average:
Weighted Average = Sum of Weighted Scores / Sum of Weights
Step 1: A teacher has conducted unit test for the 5th class, quiz and final exam. The weights of the exams are : 15 %, 20 % and 65 % and you have scored 80 in unit test, 75 in quiz and 89 in final exam. What is the weighted average?
Unit Test = 15% = 15 / 100 = 0.15
Quiz = 20 % = 20 / 100 = 0.2
Final Exam = 65 % = 65 / 100 = 0.65
Unit Test = 80
Quiz = 75
Final Exam = 89
Step 2: Substituting the values in the given formula,
Weighted Average = [(80 x 0.15) + (75 x 0.2) + (89 x 0.65)] / (0.15+0.2+0.65) = [12+15+57.85 ] / 1
Hence, 84.85 is the weighted mean of the given data.