#
# Written by:
# -- 
# John L. Weatherwax                2009-04-21
# 
# email: wax@alum.mit.edu
# 
# Please send comments and especially bug reports to the
# above email address.
# 
#-----

library(DAAG)
library(lattice)

par(mfrow=c(1,2))
hist( possum$earconch, main="" )
boxplot( earconch ~ sex, data=possum, horizontal=TRUE )
par(mfrow=c(1,1))

par(mfrow=c(1,2))
hist( possum$earconch[possum$sex=="f"], border="red", main="" )
hist( possum$earconch[possum$sex=="m"], border="blue", main="" )
par(mfrow=c(1,1))

histogram( ~ earconch | sex, data=possum ) 

fden = density( possum$earconch[possum$sex=="f"] )
mden = density( possum$earconch[possum$sex=="m"] )
xlim = range( c(fden$x,mden$x) )
ylim = range( c(fden$y,mden$y) )
plot( fden, col="red", xlim=xlim, ylim=ylim, main="" )
lines( mden, col="blue", lty=2 )


print(densityplot(~earconch, data=possum, groups=sex), main="")


fhist = hist( possum$earconch[possum$sex=="f"], plot=F, breaks=seq(from=40, to=58, by=2) )
mhist = hist( possum$earconch[possum$sex=="m"], plot=F, breaks=seq(from=40, to=58, by=2) )
ylim = range( fhist$density, mhist$density )
plot( fhist, freq=F, xlim=c(40,58), ylim=ylim, border="red", main="" )
lines( mhist, freq=F, border="blue", lty=2 )


print( histogram( ~earconch | sex, data=possum ), main="" )