## BERD R Short Course
## Session 3 Homework Key

###Q1
library(MASS)
attach(cats)
#a
par(mfrow=c(1,2))
hist(Bwt,breaks=20,prob=T,main='hist of Bwt',xlab='Bwt(kg)',col='Red')
d1<-density(Bwt)
lines(d1)
hist(Hwt,breaks=20,prob=T,main='hist of Hwt',xlab='Hwt(g)',col='Blue')
d2<-density(Hwt)
lines(d2)

#b
par(mfrow=c(1,2))
qqnorm(Bwt)
qqline(Bwt)
qqnorm(Hwt)
qqline(Hwt)

#c
par(mfrow=c(1,3))
plot(Bwt,Hwt,col='Red',xlim=c(0,4),ylim=c(6,22),main='Overall Plot',xlab='Bwt',ylab='Hwt')
l1<-lm(Hwt~Bwt)
abline(l1)
plot(Bwt[Sex=='F'],Hwt[Sex=='F'],col='Blue',xlim=c(0,4),ylim=c(6,22),main='Plot for Female',xlab='Bwt',ylab='Hwt')
l2<-lm(Hwt[Sex=='F']~Bwt[Sex=='F'])
abline(l2)
plot(Bwt[Sex=='M'],Hwt[Sex=='M'],col='Green',xlim=c(0,4),ylim=c(6,22),main='Plot for male',xlab='Bwt',ylab='Hwt')
l3<-lm(Hwt[Sex=='M']~Bwt[Sex=='M'])
abline(l3)

detach(cats)

###Q2
attach(ToothGrowth)
#a
par(mfrow=c(1,3))
boxplot(len~supp,main='len by supp',xlab='supp',ylab='length of odontoblasts')
boxplot(len~dose,main='len by dose',xlab='dose',ylab='length of odontoblasts')
boxplot(len~supp+dose,main='len by supp and dose',xlab='supp by dose',ylab='length of odontoblasts',col='red')

#b
len_R<-len
len_R[len>=4 & len<6]<-'Tiny'
len_R[len>=6 & len<12]<-'Small'
len_R[len>=12 & len<18]<-'Medium'
len_R[len>=18 & len<26]<-'Big'
len_R[len>=26]<-'Huge'
slices <- table(len_R)
lbls <- c("Big", "Huge", "Medium", "Small", "Tiny")
pct <- round(slices/sum(slices)*100)
lbls <- paste(lbls, pct) 
lbls <- paste(lbls,"%",sep="") 
pie(slices,labels = lbls, col=rainbow(length(lbls)),main="Pie Chart of Tooth")