The average (arithmetic mean) is equal to the sum of the n numbers divided by n:

Average =

sumcount

=

a_{1}+a_{2}+...+a_{n}n

Example

The average of 1,2,5 is:

Average =

1+2+53

= 2.667

Weighted average calculator

Weighted average calculation

The weighted average (x) is equal to the sum of the product of the weight (w_{i}) times the data number (x_{i}) divided by the sum of the weights:

Example

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.