## 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.**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.**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. **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.**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.