In this section we will look at how vertical line diagrams can be used to display discrete quantitative data.
Discrete quantitative data is data which can only take specific numerical values (e.g. Marks out of ten in a test).
Example
The marks below were scored by the children in a class on their maths test. All the marks are out of ten.
To organise these data, a tally chart has been produced. We first saw tally charts in book 7A.


The vertical line diagram for this data is shown on the right.
The height of each bar represents the frequency.
For example: 
(a) What is the most common mark?  
(b) What is the highest mark?  
(c) What is the lowest mark?  
(d) What is the difference between the highest and lowest marks?  


