Covariance of return and employment status 

How would we compute the sample covariance of return status and employment status ? If possible please show me the whole process of how you would go about solving getting the covariance including the formula. Problem 3. Post Katrina employment in New Orleans. The following table has information about home location and employment status of NewOrleans residents taken from the US. Current Population Survey in August 2006, a yearafter hurricane Katrina in?icted severe damage on the Gulf Coast. Observations are madeon 249 randomly selected survey respondents who had to evacuate their home due to thehurricane. The table entries are the number of survey respondents. Employed Unemployed TotalReturned to pre storm address 139 8 147 Have not yet returned