china is 7200 miles from the us, has a nominal gdp of 12 trillion (120 hundred billion), and does not primary speak english. estimate us imports from china (remember that to go from log(x) to x you need to exponentiate). c. suppose that one wanted to test if barriers to trade (distance or linguistic) did not matter for trade flows. i.e., one wanted to test if the coefficients on distance and english were both 0. how would one set this up if the error are homoscedastic? d. suppose that the r2 from the unrestricted regression is .9 and the r2 from the restricted regression is .88. what is the minimum number of countries (n) you would need in the sample for this hypothesis to be rejected