Data is split into two dataframes

library(dplyr)
enclosed = filter(sidewalk,sidewalk$Sidewalk.Cafe.Type == "Enclosed")
unenclosed = filter(sidewalk,sidewalk$Sidewalk.Cafe.Type == "Unenclosed")

Boxplot

boxplot(enclosed$Lic.Area.Sq.Ft,unenclosed$Lic.Area.Sq.Ft, names = c("Enclosed","Unenclosed"), main = "NYC Sidewalk Cafe Size")