# 11.7 Data Visualization

In this unit, you have seen how to visualize data as graphs, bar charts, and pie charts. However, there are many other exciting ways of presenting data, including interactive displays. As an example, watch the video clip below. It summarizes 200 years of world development for 200 countries in just four minutes! Note that in this visualization, the scale on the horizontal axis is not a uniform scale. Each value marked on the scale is ten times the value marked on its left (this is a logarithmic scale and if you continue with your math study you will come across this).

The Joy of Stats [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)]

You can visit the Gapminder website if you would like to investigate this graph further. This gives you the opportunity to add different countries to the graph or just concentrate on one at a time—don't spend too much time playing, though!

This dynamic chart of world development used a huge amount of data. Recently, more and more government and public data have been made freely available online. For example, you can check how the U.S. government is spending its money at the USAspending.gov site.

Freely available data allows different data sets to be combined and then displayed with powerful results. These combined data displays are known as mashups. The Year Open Data Went Worldwide is a video clip which shows the inventor of the World Wide Web, Sir Tim Berners-Lee, describing how data mashups have helped in a court case, in the Haiti earthquake disaster, and in providing information about local areas.

Remember that the same principles for reading charts and graphs that you met earlier also apply to mashups.

In particular:

• Do you know what data have been used?
• Do you know the source of the data?
• Have the data been selected to support the author’s point of view?

In this unit, you have learned how to describe a data set by using an average value and the spread of the data set. You have also learned how to draw and interpret different charts and graphs. You will find these skills helpful in your everyday life, as well as in your future studies.

11.6.1 Reading a Graph with Caution!

11.8 Self-Check