In the rich country of Emerald, the mean income is £20,000.
In the poorer, neighbouring country of Flint, the mean income is £16,000.
Charlie lives in Emerald and earns £18,000 a year.
He moves to Flint and says "I've made both countries richer!"
What does he mean?
Charlie thinks that the mean income in both countries has increased.
Can you convince yourself that Charlie is right?
What other effects can moves between countries have on the mean incomes?
Describe what is required for moves to:
Would it be possible for someone to move from Emerald to Flint and reduce the mean income in Emerald and double the mean income in Flint?