288 STATISTICS •^ LINE GRAPHS
Let’s look at this line graph.
It shows the average monthly
temperatures recorded in Maths
Town over one year.
The graph makes it easy to
see which were the warmest
and coldest months of the year.
It also lets us compare the
temperatures in different months.
The months of the year
are listed on the horizontal
x axis, and a temperature scale
runs up the vertical y axis.
The average temperature for
each month is plotted with
an “x”. All the crosses are linked
to form a continuous line.
Line graphs
On a line graph, frequencies or measurements are plotted as
points. Each point is joined to its neighbours by straight lines.
A line graph is a useful way to present data collected over time.
x axis marked with
months of the year
July was the
warmest month
January was the
coldest month
May was cooler
than August
y axis marked with
temperature scale
Markings on the axes
are evenly spaced
JanuaryFebruary March
April May June July August
September OctoberNovemberDecember
30
TEMPERATURE (°C)
MONTH
Average (mean) temperatures over a year
25
20
15
10
5
0
35
Counting the beats
A heart monitor is a machine
that records how fast your heart
is beating. It shows the data as
a line graph like a wiggly line
on a screen or print out.
REAL WORLD MATHS
Line graphs are great for
showing data over
a length of time.
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