## Plotting commands:

Hospital<- read.table("c:/413/APPENC01.txt",header=F)
Hospital<-edit(Hospital)
summary(Hospital$V2) 
mean(Hospital$V2) 
sd(Hospital$V2) 

par(mfrow=c(1,2))
hist(Hospital$V2,breaks=seq(4,20,by=4),xlim=c(0,25),ylim=c(0,90),xlab="Length of Stay",main="SENIC Project")
hist(Hospital$V4,xlab="Infection Risk", main="SENIC Project")

par(new=T)  
plot(density(Hospital$V2), type="l", xlim=c(0,25),ylim=c(0,0.25),xlab="",ylab="",main="")
dev.off()

#note: V2=Length of Stay, V4=Infection Risk
attach(Hospital)
plot(V4,V2,ylab="Length of Stay", xlab="Infection Risk", main="SENIC Project")
detach(Hospital) 

plot(V2~V4, data=Hospital,type="b") 

par(mfcol=c(1,2), pch=16) 
library() 
library(MASS) 
attach(Animals)
plot(body,brain)
plot(log(body),brain^0.1) 
detach(Animals)

# Looking for correlations among variables

# Often, it helps to look at it first.
bears<-read.table("c:/413/beardata.txt",header=T)
attach(bears)
names(bears)

pairs(bears, main="Scatterplot matrix of bear data")
cor(bears)
cor(AGE,LENGTH) #can do them separately...

## regression stuff

#simple linear regression

Bear <- lm(AGE~WEIGHT)
summary(Bear)
plot(WEIGHT,AGE,main="Regression of WEIGHT on AGE") 
abline(Bear) 
anova(Bear) 

detach(bears)