(12 points) To analyze the effect of an increase in immigrants on the employment of natives in local labor markets, various studies have used a quasi-experiment whereby US President Jimmy Carter removed all travel restrictions from Cuba to USA in 1980. This removal of restrictions led to the sudden arrival of thousands of l ow-skilled Cuban immigrants to the city of Miami in Florida, USA but not in other cities in the US. Researchers have used this to examine the effects of increases in immigration on unemployment. Most studies have used a difference-in-difference design whereby changes in the unemployment rates of low-skilled (less than high school education) native workers (both black and non- black) in Miami were compared to changes in unemployment rates for low-skilled native workers in four comparison cities not affected by the sudden increase in immigrants. The following information is provided. Each cell indicates the average unemployment rates (in percentages) of low-skilled native workers before and after the sudden immigration in Miami and the four comparison cities. 1979 1981 Miami 5.1 3.9 Four Comparison Cities 4.4 4.3