### Histogram

Similar in look to a horizontal bar graph except the bars are connected to each other, histograms are formed from grouped data to display frequencies or relative frequencies (percentages) for each class in a sample.

### Scattergrams

A method of displaying the correlation between two or more variables, including a line of best fit to demonstrate how far each observation deviates from the mean.

### Frequency polygon

Line chart plotted at the mid-point of each class, with the classes grouped e.g. into 0-10, 11-20, etc.

### Box plots

A one-dimensional graph based on the numerical data from the five-number summary.

### Stem and leaf plots

A visualisation organising numerical data into categories based on place value. These contain more detail than a standard histogram. The stem is the left hand column containing the digits in the largest place and the leaf on the right hand column contains the digits in the smallest place.

### Venn diagram

Presented as two or more circles overlapping each other to demonstrate relationships between variables.

**Example:** Animals with two legs and animals who can fly. Some would show in one group or the other and some would overlap into both groups.

### Tree diagram

A branching diagram which lists all possible outcomes of an event.

**Example:** The first branch could be Europe, the second branches splitting out Germany, France and Spain and then the third branches split out the various cities in those countries.