The most common measure of central tendency is the Mean. It is merely the average of all observations.

The data may be given as discrete series or as continuous series.

This post will describe how to calculate the mean of data in discrete series.

Example:

The cost (₹) of a 1 kg chocolate cake in 5 bakeries in a city is as follows:

250 300 350 300 400

What is the average cost of a 1 kg chocolate cake in the city?

Mean is given by the equation:

Mean = Sum of all the observations/ Total number of observations

In statistics, they came up with a cool way of saying “Sum of all the observations” in short- they assigned a symbol to that phrase, ∑ (Sigma).

So, whenever you see a ∑ sign, add up all the values that follow.

Mathematically, Mean is given by the equation:

Mean = ∑ x*i/ *n { x*i *: All values of x from 1 to n; n: Total number of observations}

The mean of values in our example is calculated as follows:

Mean = ∑ (250+ 300 + 350 +300 +400)/ 5

= 1600/ 5

= ₹ 320

Therefore, the average cost of a cake in the city is ₹ 320

**Summary:**

**The mean of discrete series is obtained by simply adding up all the observations and then dividing the sum by the total number of observations.**

###### Related articles

- Measures of Central Tendency : Introduction (communitymedicine4asses.wordpress.com)