Transcript 3. F6 Pictograms, Bar Charts and Line Graphs - Chartwell

Teach GCSE Maths
Pictograms
Number of Parking Tickets
40
30
20
10
0
Monday
Tuesday
Wednesday
Thursday
Friday
Bar Charts
and
Line Graphs
Pictograms, Bar Charts
and Line Graphs
Data from the Office for National Statistics which is included in this presentation
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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
20
Tuesday Wednesday Thursday
20
5
35
Friday
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.
Number of Parking Tickets
Monday
Tuesday Wednesday Thursday
20
20
5
35
Friday
40
e.g. A pictogram
of the
data. Tickets
Number
of Parking
pictogram  picture
Monday
Tuesday
Wednesday
Thursday
Friday
Decide with your partner how many real cars
The diagram must have a titleKey:
and key. = 10 cars
are represented by a picture of a car. Ans: 10
There is very little difference between a pictogram
and a bar chart.
We replace the pictures with bars !
Number of Parking Tickets
Monday
Tuesday
Wednesday
Thursday
Friday
0
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.
40
To find the mean number of
tickets issued per day, we
sum the frequencies and
divide by the number of days.
0
30
20
10
0
30
Friday
Friday
20
Thursday
Thursday
Wednesday
10
Tuesday
0
Monday
Friday
Wednesday
10
Thursday
Tuesday
20
Monday
30
Wednesday
20
Tuesday
30
10
Monday
40
0
Number of Parking Tickets
40
Number of Parking Tickets
Number of Parking Tickets
Number of Parking Tickets
40
Bar charts are often drawn with the bars going up
the page.
Bar charts are often drawn with the bars going up
the page.
Number of Parking Tickets
Number of Parking Tickets
40
Monday
30
Tuesday
Wednesday
20
Thursday
10
Friday
0
10
20
30
40
mean number of tickets
issued per day
= 20 + 20 + 5 + 35 + 40 = 24
5
0
Double, or dual, bar charts can be used to compare data.
(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
Methods of
Transport to School
12
10
Frequency
Frequency
This chart compares the
way that boys and girls
in a junior class travelled
to school.
With your partner
answer the following:
8
6
4
2
0
Boys
Girls
(c) Walking
A line graph is mostly used when data are given at
regular intervals of time. For example, times of day,
months, or years.
Number
Year
(millions)
e.g. The table shows the total
number of recorded crimes in
1991 15.1
England and Wales.
1993 18.4
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.
1995
19.2
1997
16.5
1999
14.8
2001
12.6
Source: Office for National Statistics:
British Crime Survey, Home Office
Solution:
1991
Number
(millions)
15.1
1993
18.4
1995
19.2
1997
16.5
1999
14.8
2001
12.6
Number (millions)
Year
Total Number of Crimes
committed in England and Wales
x
x
x
x
x
x
Year
• Between
1991
and 2001
, most
crimes
1995.
Tell your
partner
2 things
the
graphoccurred
tells youinabout
• Crime decreasedthe
each
year from
1995 to 2001.
number
of crimes.
( Other answers are possible. )
Exercise
1. The diagram shows the spending by overseas
tourists in parts of the U.K. in 2001.
Area
Scotland
Wales
Heart of England
SW England
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 £450 000 000.
How many pictures would show this?
Exercise
Answers:
Area
Scotland
Wales
Heart of England
SW England
Source: Office for National Statistics
Key:
= £100 million
(a) (i) £700 million was spent in the Heart of England
(ii) £250 million was spent in Wales.
(b) 4½ pictures are needed to show £450 000 000.
2. The diagram shows the estimates of fish stock
in the North Sea in the 1970s and 1990s.
3000
North Sea Fish Stocks
Frequency 2000
( thousands
of tonnes ) 1000
0
70's
90's
Cod
Herring
Haddock
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: 800 000 ( 800 thousand ) tonnes
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.