A real variable is one that has been adjusted for inflation, reflecting the true purchasing power of money. In contrast, a nominal variable is measured in current prices and does not take inflation into account.
Among the options provided:
a. the nominal interest rate - This is not a real variable, as it does not account for inflation. b. the ratio of the value of wages to the price of soda - This represents a real variable, as it relates wages (which can be seen in real terms) to the price of a good. c. the price of corn - This is generally considered a nominal variable, as it reflects current market prices without an adjustment for inflation. d. the dollar wage - This is also a nominal variable, as it reflects the current wage rate without accounting for inflation.
Given these interpretations, the best answer indicating a real variable is:
b. the ratio of the value of wages to the price of soda.