The Friday File: Based on the idea that exchange rates and prices eventually adjust to make the same thing equally priced the world over, the Big Mac Index was created. In Norway, a Big Mac is $7.84, in Switzerland $7.12 and Brazil $5.64, all overvalued currencies. But it’s just $2.03 in South Africa and $2.57 in China, both countries I’ll be economically eating my way through before their currencies rise.