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Creating and Understanding Pie
Charts
What is a Pie Chart?
A pie chart is a circular chart (pie-shaped); it is split into segments to show percentages or the relative contributions of categories of data.
Survey of female hair colour
Red7%
Brunette39%
Blonde47%
Multi- coloured
7%
How do I draw a pie chart?Step 1
1. Decide on the total number of categories. In other words, identify the categories that you will use.
2. Collect the data so the number per category can be counted (Frequency Table)
Brand Name Tally FrequencyDaz |||| |||| |||| |||| |||| |||| |||| |||| 40
Ariel |||| |||| |||| |||| |||| |||| |||| |||| |||| |||| |||| |||| 60
Bold |||| |||| |||| |||| |||| |||| |||| |||| |||| |||| 50
Fairy |||| |||| |||| |||| |||| 30
Other |||| |||| |||| |||| 20
TOTAL 200
How do I draw a pie chart?Step 2
Brand Name
Units sold / year in 106 Degree Share
Daz 40 x 360 = 72o
Ariel 60 x 360 = 108o
Bold 50 x 360 = 90o
Fairy 30 x 360 = 54o
Other 20 x 360 = 36o
Total 200 Total = 360o
To calculate degree share, you need to divide the share that the category has by the total units and then multiply by 360 (there are 360 degrees (°) in a circle).
40
200
60
20050
200
30
200
20
200
How do I draw a pie chart?Step 3 – Drawing the chart
1st Draw a Circle With a protractor measure 72o Mark this angle and draw a line from the centre to the mark
Turn the protractor so that the zero is now on this line
Now measure 108oNow measure 90o
And finally 54o
You should now be left with 36o
Again, turn the protractor so that zero is now on this line
Again, turn the protractor
Lightly, draw a vertical line through the centre
Please note that due to the limitations of the software some measurements on this
screen are not totally accurate.
How do I draw a pie chart?Step4It may be necessary to work
out the percentage and include this in the labelling. How would we do this?
Brand Name
Units sold /
year in 106
% age
Daz 40(40 ÷ 200) x 100
= 20%
Ariel 60(60 ÷ 200) x 100
= 30%
Bold 50(50 ÷ 200) x 100
= 25%
Fairy 30(30 ÷ 200) x 100
= 15%
Other 20(20 ÷ 200) x 100
= 10%
Total 200
To calculate degree share, you need to divide the share that the category has by the total units and then multiply by 100 (the whole circle is equal to 100%).
Market share of soap powder brands
Daz20%
Ariel30%
Bold25%
Fairy15%
Other10%
ExercisesUse a pie chart to illustrate the data given below, fully label
the chart and show the percentage value of each sector.
180 FE college students were asked what they intended to do next year.
54 Going to university
40 Staying at college
62 Going into employment
24 No firm intention
Exercises
At a concert, the ages of 115 people were recorded as:
Under 20 15
20 - 29 30
30 - 39 22
40 - 59 24
60 and over 24
Draw a pie chart using this data, give the data labels values in % ages
Thirty people were surveyed in a shopping centre and asked their ages. These are displayed below.
54 41 65 46 66 3732 71 34 73 15 2664 22 54 8 58 4314 57 43 52 24 6843 39 59 35 48 49
a) Draw a tally-frequency table.b) Using the data in your frequency table, construct a table
to calculate the angles in a pie chart.c) draw and fully labelled a pie chart to show the
percentage values.