xyplot(Ozone~Wind | Month,data=airquality,layout=c(5,1))
histogram(~Sepal.Length|Species,data=iris)
bwplot(Sepal.Length~Species,data=iris)

require(UsingR) #opens the functions and data of 
#the package UsingR
attach(kid.weights) #allows to write height 
#instead of kid.weights$height...
histogram(~weight|gender,data=kid.weights,layout=c(1,2))
histogram(~height|gender,data=kid.weights,layout=c(1,2))
mean(weight[gender=="M"])
mean(weight[gender=="F"])
mean(height[gender=="M"])
mean(height[gender=="F"])

H=read.csv(file="male_female_over_20_heights.csv")
str(H)
histogram(~H$height|H$gender,layout=c(1,2))