Pie Charts. Why a Pie Chart? □Very visual □Easy to read □Slices show clearly how the data is...

Pie Charts

Why a Pie Chart?

□Very visual □Easy to read□Slices show clearly how the data is

distributed

Data for a Pie Chart

□ Usually given in a table format

□ This data was obtained from a class survey on “Favourite Drinks”

Favourite Drink

Frequency

Milk 7

Orange 9

Cola 13

Water 6

Tea 2

Other 3

These are the answers given

Other allows for

“unexpected” answers

How many people said

they preferred this drink

1 Work out the slicesFavourite Drink

Frequency

Milk 7

Orange 9

Cola 13

Water 6

Tea 2

Other 3

Total 40

We need to calculate the size of each slice inthe pie chart

40 people responded to the survey

If very person had theirown slice, each would get the same

140

of the circleX 360º= 9º

If 1 person is 9º

Angle

Total 360º

Favourite Drink

Frequency

Milk 7

Orange 9

Cola 13

Water 6

Tea 2

Other 3

9 x 9

13 x 9

6 x 9

2 x 9

3 x 9

7 x 9 = 63º

= 81º

= 117º

= 54º

= 18º

= 27º

2 Draw the Pie Chart

Mark a centre for the Pie Chart

x

Draw a circle with centre on the markUse compassesOr draw around an Angle Measure

x

2 Draw the Pie ChartDraw line vertically from centre to circumference

Draw LARGEST slice firsti.e. Cola = 117º

Cola

Label the slice ‘Cola’

Do not enter the angle or the frequency!

x

2 Draw the Pie Chart

Draw NEXT LARGEST slice i.e. Orange = 81º

Turn Protractor so that0º marker is at the endof line just drawn

Orange

Cola

2 Draw the Pie Chart

Then Milk = 63º

Orange

Cola

Milk

2 Draw the Pie Chart

Then Water = 54º

Orange

Cola

Milk

Water

2 Draw the Pie Chart

Then Other = 27º

Orange

Cola

Milk

Water

Other

2 Draw the Pie Chart

The LAST slice is already drawn – just check itTea = 18º

Orange

Cola

Milk

Water

Other

Tea

Remove the small guide marks carefully

Give the Pie Chart its Title

Class 7A’s Favourite Drink