Hi..i'm a master student in UK. i plan to do research in the topic of carry trade to test risk and return...There are many paper about this topic ,which they explain about the formula they used but i still don't understand which data of exchange rate they use and where i can find it... for example they use shape ratio to calculate risk but which data they use...do u have any suggestion about the formula and how to calculate risk and return on carry trade?  

thank you..