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Exploring data: graphs and numerical summaries
Figure 1 Tattoo sizes
Activity 3: Tattoo sizes
Calculate the angles that represent the numbers of medium and small tattoos.
View answer - Activity 3: Tattoo sizes
Once you have calculated the angles, you draw in the three radii that subtend them,
and then shade the three sectors in order to distinguish them from each other.
At first sight the pie chart seems to fulfil the basic requirements of a good statistical
display: it appears to be informative, easy to construct, visually appealing and readily
assimilated by a non-expert.
Pie charts can be useful when all you want the reader to notice is that there were more
large than medium size tattoos, and more medium than small tattoos. But in
conveying a good impression of the relative magnitudes of the differences, they have
some limitations. Also pie charts are useful only for displaying a limited number of
categories, as the next section illustrates.
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22nd February 2016
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