It is one of the most common and popular measure of central tendency. It is defined as the sum of all the observations divided by the number of observations. It is denoted by A.M.

The major problem with A.M is that if the differences among observations are high, then this average will give the misleading result and this average will not be a representative of the population to which it belongs.

**Formula**

Arithmetic mean = Sum of the observations / Number of observations

**Example**

Find Arithmetic mean of the number 5, 6, 9, 10, 11 and 15.

**Solution**

Arithmetic mean = Sum of the observations / Number of observations = 5 + 6 + 9 +10 + 11 + 15 / 6 = 9.3