Spearman's rank: Economic development and life expectancy
In this A-level resource, students investigate the relationship between GDP per capita (as a measure of economic development) and average life expectancy for a range of different countries.
They plot a scattergraph of the data, draw a line of best fit and interpret the graph, suggesting explanations for anomalies.
They then calculate the Spearman's rank correlation coefficient, carry out a significance test and explain why there appears to be a relationship between gross domestic product and life expectancy.
Answers to the scattergraph and Spearman rank activities are provided in the Excel spreadsheet (the second downloadable file). Suggested answers to the interpretation questions are provided in the worksheet.
An extract from the suggested answers:
3. Using the data analysis you have completed, explain why there appears to be a relationship between the GDP per capita and average life expectancy for these countries.
Expect to see answers that provide the following conclusions:
- The statistical analysis shows us that there is a positive correlation between the two pieces of data as the value is nearer to 1.
- The scattergraph shows a positive correlation from our line of best fit.
- Life expectancy generally decreases as GDP per capita decreases; however, there are anomalies such as North Korea. As geographers, we know that increased GDP per capita means more money for healthcare, more nutritious food and an increased quality of life; therefore, we would expect a positive correlation between the two sets of data.
