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Charts

Here is a list of the most common charts.

For each chart we will show the distribution of the percentages 45%, 33% and 22%.



Pie chart

A pie chart or circle chart can be used, if the data is a part of a given total quantity, like, for instance, when we want to illustrate the distribution of the votes in elections.
Example of a pie chart

Advantages:
The distribution of the data is clearly represented and easy to understand.
It’s difficult to manipulate the way the data appear.

Disadvantages:
It’s difficult to draw by hand (you need protractor, compass, ruler etc.).
All data must be converted to degrees.
You cannot read the data accurately just by looking at a pie chart, unless the percentages is written on it, like in the figure to the right.



Tree maps

A tree maps consist of squares, each of which correspond to a given value. Different percentages can be shown with different colors. Tree maps are used, if the data is a part of a given total quantity, like, for instance, when we want to illustrate the distribution of the votes in elections.
Tree map statistic

Advantages:
It’s easy to draw.
It is reasonable easy to read. You can count the number of squares.
It’s difficult to manipulate the way the data appear.

Disdvantages:
Only percentages given as whole numbers can be expressed.
You can only read it by counting.

Bar chart

A bar chart or bar graph is a chart with rectangular bars, the lengths of which is proportional to the data they represent.
Bar chart example

Advantages:
It is reasonable easy to read.
It can be read directly.
It is reasonable easy to draw.
It can be used for almost all kind of observations.

Disadvantages:
It is easy to manipulate the way the data appear.

Line chart

A line chart’s data are represented with dots connected by lines.
Example of a line chart

Advantages:
It is reasonable easy to read.
It can be read directly.
It is reasonable easy to draw.
You can show a development of data, because the data are connected.
It can be used for almost all kind of observations.

Disadvantages:
The chart cannot be exactly read on the lines connecting each data point.
It is easy to manipulate the way the data appear.
It's not a good way of expressing the distribution of data, given as percentages of a total quantity.