The three most common measures of average are given by the mean, median and mode.

Before we explore these concepts, let’s first distinguish between Discrete versus Continuous and Grouped versus Ungrouped:

**Discrete versus Continuous…TBC**

**Grouped versus Ungrouped…TBC**

# Measures of Central Tendency & Variation

The best way to illustrate the differences between the mean, median and mode is to consider a given set of numbers. For example:

### Mean

The mean is found by adding all of the data values together and dividing by how many there are.

### Median

The median is the middle data entry once all of the data values have been put into ascending order.

Note that the middle data entry is only explicitly clear when there is an odd number of data points.

### Mode

The mode is the most common.