#Load libraries
library("sandwich")
library("lmtest")

  #Load Data
data <- read.csv("C:/Users/Benja/Downloads/DvDData.csv" , header=TRUE, sep=",")

  #Run ordinary least squares
ols <- lm(Difference ~ RuralUrbanContinuumCode2013 + ManufacturingDependent2000 +	HiAmenity +	HiCreativeClass2000 +	Low_Education_2015_update +	PopChangeRate1019 +	Net_International_Migration_Rate_2010_2019 + Dominion,  data = data)

  # Test non-weighted regular standard error
summary(ols)

  # Test non-weighted using robust standard error
coeftest(ols, vcov = sandwich)


  # Run weighted least squares
wls <- lm(Difference ~ RuralUrbanContinuumCode2013 + ManufacturingDependent2000 +	HiAmenity +	HiCreativeClass2000 +	Low_Education_2015_update +	PopChangeRate1019 +	Net_International_Migration_Rate_2010_2019 + Dominion, weight = TotalVotes,  data = data)

  # Test coefficent using regular standard error   
summary(wls)

  #Test coefficient using robust standard error
coeftest(wls, vcov = sandwich, cluster = ~ TotalVotes)