Create and interpret column or bar graphs

Column and bar graphs are used to display, interpret and compare categories of data that have been counted. Bar graphs can run vertically or horizontally, but column graphs only run vertically. We can compare more than one set of data on one graph, using different colours.

 

We use ticks to represent the numbers between the main number points, as seen below:

Let's think about how we read this graph:

• Notice how the horizontal axis says "Sales ('000)." This means that the scale is in thousands. For example, the number $4$4 represents $4000$4000 and $5$5 represents $5000$5000. The number correspond to the ticks that have vertical lines above them.
• There are $5$5 ticks between the numbered lines, so to work out how much each tick is worth, we use division: $1000\div5=200$1000÷​5=200, so each tick is worth $200$200.
• Then we can work out the sales for each company. For example, $4200$4200 Mazdas were sold, because the graph shows it is $4000$4000 + one segment, or $200$200.

 

Worked Examples

Question 1

Question 2

Question 3