10182

# African GDP Outliers

For the most part, African national GDP data for individual countries for 1970–2008 correlates very strongly, with pairs of data showing a correlation of more than 0.9. Connecting such pairs of "strongly" correlated countries together creates a graph containing most countries. The indirectly correlated countries are those that are connected to each other only via other vertices. Countries that correlate "weakly" are isolated vertices. It may be interesting to examine the GDP data with respect to historic events like a change of government, civil wars, and so on.
Also shown are correlations for land areas and population.

### DETAILS

Most of the GDPs of African countries from 1970–2008 are highly correlated. Using the built-in Mathematica function CountryData, the GDPs are correlated. You can choose the countries with the largest population, the largest land area, or the largest GDP. You can also choose how many countries to view. The GDP data that does not correlate strongly with other countries (correlation < 0.9) is identified using a copy of the graph theory technique described in [1].
The GDPs of pairs of countries can be compared by clicking the "compare GDP" button and selecting two countries.
The "graph" button shows how the GDP data of a selected country correlates with data from other countries. The graph (see below) is constructed linking pairs of countries whose GDPs showed a greater than 0.9 correlation.
The correlation of a country with itself is always equal to 1 and is denoted as an "absolute" correlation.
If the correlation of the second country's data with the first country's data is greater than 0.9, it is deemed to be "strongly" correlated and is directly connected to the first country in the graph.
An "indirectly" correlated country is one whose correlation with the selected country is less than 0.9 but is linked to the selected country via other countries.
A "weakly" correlated country is one whose correlation with the selected country is less than 0.9 and is not linked to the selected country via other countries.
The "distance" between two countries is the number of graph vertexes traversed to get from one country vertex to the other. If there is no connection between countries, then the distance is infinity; the distance from a country to itself is zero.
Reference
[1] S. Chen, "Graph Theory and Finance in Mathematica," Wolfram Blog (blog). (Jun 1, 2012) blog.wolfram.com/2012/06/01/graph-theory-and-finance-in-mathematica.

### PERMANENT CITATION

 Share: Embed Interactive Demonstration New! Just copy and paste this snippet of JavaScript code into your website or blog to put the live Demonstration on your site. More details » Download Demonstration as CDF » Download Author Code »(preview ») Files require Wolfram CDF Player or Mathematica.

#### Related Topics

 RELATED RESOURCES
 The #1 tool for creating Demonstrations and anything technical. Explore anything with the first computational knowledge engine. The web's most extensive mathematics resource. An app for every course—right in the palm of your hand. Read our views on math,science, and technology. The format that makes Demonstrations (and any information) easy to share and interact with. Programs & resources for educators, schools & students. Join the initiative for modernizing math education. Walk through homework problems one step at a time, with hints to help along the way. Unlimited random practice problems and answers with built-in Step-by-step solutions. Practice online or make a printable study sheet. Knowledge-based programming for everyone.