You want to analyze how COVID-19 vaccine mandate affects infection rate in the World.

You collect data for every country where the information is available.

a) What is the unit of observation? What type of data structure is it? List the variables of interest you would use for this analysis: Clearly state the dependent, the main independent and the controls variables.

b) Specify the model that you will run and interpret each coefficient in the model and their expected signs.

c) What is the main hypothesis you are testing? Specify the null, the alternative, and the associated test statistic.

One of your classmates argues that some countries have comparative advantages due to climate or density of the population. You collect data to classify if a country has a comparative advantage or not.

d) How would you create a variable that capture these differences in countries?

e) Write down a regression model that will estimate the effect of vaccine mandate on infection rate while accounting for countries comparative advantages.

f) Test the hypothesis that the effect of vaccine mandate on infection rate differ according to countries comparative advantages: Specify the null, the alternative, and the associated test statistic.