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Part 9:
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Pie Charts |
| If you wish to illustrate some information using a pie chart you
need first of all to be assured that the information you have represents
the total information that is available. A pie chart is no use, for
instance, in illustrating the annual sales figures for years 1990-1997.
It can only be used where we have a number of parts making up a whole,
and is most useful when the relative proportions are more important
than the actual values. In fact, you need the same type of information as you need to draw a component bar chart. Example 9 It could be dangerous to illustrate this information with a pie chart:
We must be assured that those four makes of cars represent the totality of the sales. If we are not certain of that, we can only draw a bar chart, because we can always add on extra bars at the end without affecting any of the existing ones. |
