## Read in data
titanic <- read.delim("http://myweb.uiowa.edu/pbreheny/data/titanic.txt")
head(titanic)
nrow(titanic)
ncol(titanic)
dim(titanic)

## table
table(titanic$Class)

## Proportions
tab <- table(titanic$Class)
tab/nrow(titanic)
prop.table(tab)

## Percentages
round(100*prop.table(tab), 1)

## Two way table of class and survival
with(titanic, table(Class, Survived))

## Two way proportions
tab <- with(titanic, table(Class, Survived))
prop.table(tab)    ## Overall proportion
prop.table(tab, 1) ## Row-wise proportion
prop.table(tab, 2) ## Column-wise proportion

## Three way table of class
tab <- with(titanic, table(Class, Survived, Sex))
tab
prop.table(tab, c(1,3))

## barplot
tab <- table(titanic$Class)
barplot(tab)

## stacked barplot
tab <- with(titanic, table(Survived, Class))
barplot(tab, legend=TRUE, args.legend=list(x="topleft"))

## Loading the lattice package
require(lattice) ## or library(lattice)

## lattice barchart
tab <- table(titanic$Class)
barchart(tab)

## lattice stacked barplot
tab <- with(titanic, table(Class, Survived))
barchart(tab, auto.key=TRUE)

## Conditioning
tab <- with(titanic, table(Class, Sex, Survived))
barchart(tab, auto.key=TRUE)

## Unequal scales
barchart(tab, auto.key=TRUE, scales="free")

## Install ggplot2
## install.packages("ggplot2")

## Plotting with ggplot2
require(ggplot2)
qplot(Class, data=titanic, fill=Survived) + facet_grid(Age~Sex, scales="free")