mean

Mean is the ‘middle’ value of a set of numbers. We sometimes use ‘average’ for mean.

In order to calculate the mean of a set of data, we add the sum of the values and divide that sum by the number of values in the set.

For example, there are 5 monkeys in a zoo. Here are their weights:

    Monkey 1 = 68 kg
    Monkey 2 = 68 kg
    Monkey 3 = 49 kg
    Monkey 4 = 51 kg
    Monkey 5 = 44 kg

Mean = \dfrac{68 + 68 + 49 + 51 + 44}{5}

          = \dfrac{280}{5}

          = 56

The mean is 56 kg.

We sometimes refer to ‘mean’ as ‘arithmetic mean’.