Q1: In the research, why we choose to use ratio of expenditure on education to the total GDP in a region instead of just expenditure on education?
A1: As economic situation differs between regions, expenditure on education cannot be used as a reference.
Q2: Can correlation of two variables proven with statistical methods suggest that they have relationship in real world?
A2: Not necessarily, there can be a third variable that explains the statistical correlation of them. This does not mean the two variables have any relationship in real world.
Q3: What economic way of solving problem is used in this study?
A3: Propose a hypothesis, test it with scientific methods, then interpret the result and reach a conclusion.