How_To_Be_Good_At_Math

STATISTICS • BAR CHARTS 285

Bar charts

A bar chart uses bars or columns to represent groups or sets

of data. The size of each bar shows the frequency of the data.

Bar charts are also called bar graphs and column graphs.

To find out how many white

cars were seen, look across

from the top of the White bar to

the vertical axis. Then read the

number (5) off the scale.

We can redraw the same

chart so that the bars are

horizontal, going across the

chart, rather than vertical.

The car colours are

now along the vertical

axis, while the number of

cars (the frequency) can be

read off the horizontal axis.

Let’s look at this bar chart. It

uses data from a survey of

car colours. The bars are all the

same width, separated by gaps.

The chart is framed on two

sides by lines called axes.

The bars for car colours sit on the

horizontal axis. A scale on the

vertical axis shows the number

of cars seen (the frequency).

The height or length

of a bar shows

the frequency.

Vertical

axis

Horizontal axis

The frequency of

white cars is 5

NUMBER OF CARS SEEN

0

1

2

3

4

5

6

7

8

Silver

COLOUR OF CAR

Red Blue White Black

Look along the

horizontal axis to

find the frequency

The scale is now along

the horizontal axis

0 1 2 3 4 5 6 7 8

Black

White

Blue

Red

Silver

Car colours

COLOUR OF CAR

NUMBER OF CARS SEEN

Car colours

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