The word average mean middle or central point. Most of the time when we are required to calculate the average of a list of data we are supposed to calculate the ‘mean’ of the given data.

**Formula to calculate average** **(mean)** **for ungrouped data.**

Average is calculated by dividing the sum of the given data by the count of the same data.

**Example:**

A sample of 5 students was taken from an economics class to establish the average age of the class. The age of the students was listed as follows; 17yrs, 16yrs, 18yrs, 16yrs and 15yrs.Calculate the average age of the students.

Hence the average age of the students is 16.4 years.

**Formula to calculate average ( mean ) for grouped data.**

Here, we calculate mean by multiplying the summation of frequency and midpoint and then divide it by the total frequency.

**Example:**

Class | Frequency (f) | Midpoint (m) | Product (m x f) |

1 – 5 | 4 | 3 | 12 |

6 – 10 | 7 | 8 | 56 |

11- 15 | 9 | 13 | 117 |

Total | N = 20 | ( Σmf) = 185 |