## 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.

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

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.

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.

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

It is easy to manipulate the way the data appear.

## Line chart

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