* SD = standard deviation
Weighted average calculator
The average (arithmetic mean) is equal to the sum of the n numbers divided by n:
The average of 1,2,5 is:
Weighted average calculation
The weighted average (x) is equal to the sum of the product of the weight (wi) times the data number (xi) divided by the sum of the weights:
Find the weighted average of class grades (with equal weight) 70,70,80,80,80,90:
Since the weight of all grades are equal, we can calculate these grades with simple average or we can cound how many times each grade apear and use weighted average.