Hypothesis:
A country's GDP is the key determination of a country's happiness. Research question: To what extent does countries' GDP align with their measure of happiness? Problem statement: Examine a number of happiness indexes and see what role GDP plays in them. Literature justification for this perspective: you need to find literature that links the two.
Method
1. Identify the GDP and happiness measure of countries
2. Plot them on a single graph
3. Do some statistical analysis to see if there is any correlation. I can help you with this.
4. Compare the results to reach a conclusion about the hypothesis