Mean

The mean is the most intuitive measure of central tendency — it tells us where the "centre of mass" of the data lies. For ungrouped data, it is simply the sum of all observations divided by the number of observations, written as $\bar{x} = \frac{\sum x_i}{n}$. When data is grouped into a frequency distribution, each value is weighted by its frequency, giving $\bar{x} = \frac{\sum f_i x_i}{\sum f_i}$. This single number summarises the entire dataset into a …