\f\f\fProblem 1 Gravity Models [20 points) You are an International Economist working for the U.S. Government and you Were given the following data on the biggest Asia-Pacic economies. TB (Trade Balance] represents the sum of exports and imports of each country with the distance being measured in miles; the GDP and TB are also measured in mitlions of s. This data can be found in the spreadsheet posted in Canvas under the name \"Gravity Models Data Midterm 1". a) Briey explain what gravity models show us and why they are useful. b) Given the data, estimate statistically the effects of partners' distance and size with respect to US trade. Repeat the exercise for the three years 1995, 2000 and 2019. {Note: Make sure to do the logarithmic transformation on the data before estimating the models as shown in class.) c) Discuss the effect you obtain on Distance. Are you surprised by the results? Explain. d) Discuss the effect you obtain on Size. Are you surprised by the results? Explain