1. Bar Charts and Line Graphs
Teach GCSE Maths 40
Number of Parking Tickets 10 20 30
Monday
Tuesday
Wednesday
Thursday
Friday
Pictograms
Friday
Thursday
Wednesday
Tuesday
Monday
Bar Charts
and
Line Graphs

2. Pictograms, Bar Charts and Line Graphs
Data from the Office for National Statistics which is included in this presentation is reproduced under the terms of the click-use licence.
"Certain images and/or photos on this presentation are the copyrighted property of JupiterImages and are being used with permission under license. These images and/or photos may not be copied or downloaded without permission from JupiterImages"
© Christine Crisp

3. 20 5 35 40 Diagrams are often used to show information from data.
e.g. The following data set shows the number of cars given parking tickets on a particular street on 5 weekdays.
Monday
Tuesday
Wednesday
Thursday
Friday 20 5 35 40
As always, the frequencies are numbers, but we don’t have numbers for the days of the week.
The data are qualitative (descriptions ) instead of quantitative (quantities or numbers ).
Both types of data can be shown in pictograms and bar charts.

4. 20 5 35 40 20 Number of Parking Tickets e.g. A pictogram of the data.
Monday
Tuesday
Wednesday
Thursday
Friday 20 5 35 40 20
e.g. A pictogram of the data.
Number of Parking Tickets
pictogram  picture
Friday
Thursday
Wednesday
Tuesday
Monday
Decide with your partner how many real cars are represented by a picture of a car.
Key: = 10 cars
The diagram must have a title and key.
Ans: 10

5. There is very little difference between a pictogram and a bar chart.
We replace the pictures with bars !
Number of Parking Tickets
Friday
Thursday
Wednesday
Tuesday
Monday 10 20 30 40
As before, we must have a title but instead of a key we have a scale.
Bar charts are easier to draw using squared paper.

6. Bar charts are often drawn with the bars going up the page.40
Number of Parking Tickets 10 20 30
Monday
Tuesday
Wednesday
Thursday
Friday 40
Number of Parking Tickets 10 20 30
Friday
Thursday
Wednesday
Tuesday
Monday
Friday
Thursday
Wednesday
Tuesday
Monday
Number of Parking Tickets 10 20 30 40
Friday
Thursday
Wednesday
Tuesday
Monday
Number of Parking Tickets 10 20 30 40
Friday
Thursday
Wednesday
Tuesday
Monday
Number of Parking Tickets 10 20 30 40
To find the mean number of tickets issued per day, we sum the frequencies and divide by the number of days.

7. Bar charts are often drawn with the bars going up the page.
Number of Parking Tickets
Friday
Thursday
Wednesday
Tuesday
Monday
Number of Parking Tickets 10 20 30 40
Friday
Thursday
Wednesday
Tuesday
Monday
Number of Parking Tickets 10 20 30 40 40 30 20 10
mean number of tickets issued per day
Friday
Monday
Tuesday
Thursday
Wednesday
20 +
20 +
5 +
35 + 40 =
= 24 5

8. Methods of Transport to School
Double, or dual, bar charts can be used to compare data.
This chart compares the way that boys and girls in a junior class travelled to school.
Frequency 2 4 6 8 10 12
Bus
Train
Taxi
Walking
Methods of Transport to School
Boys
Girls
With your partner answer the following:
(a) How many girls go by train?
(b) How many children go by taxi?
(c) What is the most popular way of getting to school?
Ans: (a) 2 (b) 4 (c) Walking

9. A line graph is mostly used when data are given at regular intervals of time. For example, times of day, months, or years.
Year
Number (millions)
1991
15.1
1993
18.4
1995
19.2
1997
16.5
1999
14.8
2001
12.6
e.g. The table shows the total number of recorded crimes in England and Wales.
Draw a line graph to display the data.
Solution: We plot the years on the x-axis (horizontally) and the number of crimes up the y-axis (vertically). The points are joined with straight line segments.
Source: Office for National Statistics: British Crime Survey, Home Office

10. Total Number of Crimes committed in England and Wales
Solution:
Total Number of Crimes committed in England and Wales
Year
Number (millions)
1991
15.1
1993
18.4
1995
19.2
1997
16.5
1999
14.8
2001
12.6 x x x x x x
Number (millions)
1991
1993
1995
1997
1999
2001
Year
Between 1991 and 2001, most crimes occurred in 1995.
Crime decreased each year from 1995 to 2001.
( Other answers are possible. )
Tell your partner 2 things the graph tells you about the number of crimes.

11. Exercise
1. The diagram shows the spending by overseas tourists in parts of the U.K. in 2001.
SW England
Heart of England
Wales
Scotland
Area
Source: Office for National Statistics
Key: = £100 million
(a) How much was spent by the tourists in (i) the Heart of England and (ii) Wales?
(b) The figure for SW England was £ How many pictures would show this?

12. (i) £700 million was spent in the Heart of England
Exercise
Answers:
Area
Scotland
Wales
Heart of England
SW England
Source: Office for National Statistics
Key: = £100 million
(i) £700 million was spent in the Heart of England
(ii) £250 million was spent in Wales.
(b) 4½ pictures are needed to show £

13. 2. The diagram shows the estimates of fish stock in the North Sea in the 1970s and 1990s.
North Sea Fish Stocks
1000
2000
3000
Cod
Herring
Haddock
Frequency
( thousands of tonnes )
70's
90's
Source: Office for National Statistics
(a) Which type of fish stock increased between the 1970s and the 1990s?
Ans:
Herring
(b) What was the estimate of the stock of cod in the 1970s?
Ans: ( 800 thousand ) tonnes

14. SUMMARY
Qualitative data has descriptions instead of numbers.
e.g. days of the week, colours, transport methods.
Pictograms and bar charts can be used to display qualitative and quantitative data.
Pictograms must have a title and a key. The key gives the frequency for each picture.
The lengths of the bars on a bar chart give the frequencies. Bar charts must have a title and a scale.
Line graphs have straight line segments joining the points. The x-axis often shows time.