Data <- read.delim('http://myweb.uiowa.edu/pbreheny/data/tailgating.txt')

# Ranks
cbind(Dist=Data$Distance, Rank=rank(Data$Distance))
hist(Data$Distance, col='gray', border='white', main='', las=1)
hist(rank(Data$Distance), col='gray', border='white', main='', las=1)

# Bootstrapping the median
DrugYes <- subset(Data, Drug==1)
DrugNo <- subset(Data, Drug==0)
medYes <- medNo <- numeric(10000)
for (i in 1:10000) {
  medYes[i] <- median(sample(DrugYes$Distance, replace=TRUE))
  medNo[i] <- median(sample(DrugNo$Distance, replace=TRUE))
}
head(medYes)
head(medNo)
Diff <- medNo - medYes
quantile(Diff, c(.025, .975))