Calculate the investment in studying in a Doctoral program in the USA using NPV, IRR, PI, and discounted Payback, for each student. Initial Investment is all the same, but other expenses up to 2 years before graduation must be different, as after graduating from Doctoral USA, how much income expectations (outflows) differ from one another and the opportunity to occupy higher positions and get better salaries. Use the assumptions of discount factor, relevant cost, and relevant revenue, reasonably with reasons.