| Scatter
graphs |
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What are scatter graphs? |
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Scatter graphs have data
plotted as a series of dots or crosses (x). |
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They are drawn to see if
information about two different things is linked. |
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You should not join up the
points on a scatter graph but you could add a line of best fit. |
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What data is
plotted here? |
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If the data is linked it is
called a correlation. The better the correlation the nearer the
graph will be to a straight line. |
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Correlations can be
positive, negative or no correlation (random). |
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| Distance from source
(M) |
200 |
1100 |
1800 |
2500 |
3200 |
4000 |
4500 |
5000 |
| Average speed (M/s) |
0.6 |
0.7 |
0.5 |
0.9 |
1.0 |
1.2 |
1.5 |
1.4 |
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Sometimes there are
anomaly points that do not follow the trend
line. Can you spot them? |
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OK Let's
Try ... |
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Use a pencil
and ruler. |
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Make sure you remember all 7
instructions on the scatter graph above. We are going to plot
Infant Mortality Rate against
GNP (wealth) for 10 countries. |
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| Country |
Infant Mortality
Rate |
Life Expectancy (years) |
| Algeria |
27 |
72 |
| Uganda |
76 |
48 |
| Belize |
18 |
73 |
| Brazil |
24 |
72 |
| Indonesia |
34 |
70 |
| Bangladesh |
52 |
63 |
| UK |
5 |
79 |
| Belgium |
4 |
80 |
| Australia
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5 |
76 |
| Japan |
3 |
79 |
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Source:
www.prb.org 2008 World Population Data Sheet |
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Attach the finished graph to
your book. |
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Write a paragraph describing
what your graph shows... |
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What sort of correlation is
shown? |
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Describe any anomalies? |
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How strong is the
correlation? |
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Scatter
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