Babies 1: fig 1.4

isSmoker = bab3$smoke == 1
isNonSmoker = bab3$smoke == 0
num = table(bab3$number[isSmoker])[1:7] # table of number of cigarettes smoked per day
num = round(num*100/sum(num))
num[6] = 5 # to make the sum 100

mid.num = c(2.5, 7.5, 12.5, 17.5, 25.0, 35.0, 50.0)
num.count = rep(mid.num, num)
brk = c(0,5,10,15,20,30,40,60)
h = hist(num.count, breaks=brk,plot=F)
h$density = 100*h$density
plot(h, col="gray20", border="white", xlab="Number of cigarettes per day", ylab="Percent per cigarette", main="")