x=seq(70,130,length=200)
y=dnorm(x,mean=100,sd=10)
plot(x,y,type="l",lwd=2,col="red")
x=seq(70,90,length=100)
y=dnorm(x,mean=100,sd=10)
polygon(c(70,x,90),c(0,y,0),col="gray")


drawnormal <- function(lo,hi,color,mu=0,sigma=1,yaxis="n",xaxis="n",ann=TRUE,ymax=0,type="l",new=FALSE,xlab="x",ylab="",main="",sub="")
{
x <- seq(lo,hi,length = 100)
y <- dnorm(x,mu,sigma)
ifelse(ymax==0,ylim<- c(0,dnorm(mu,mu,sigma)), ylim<-c(0,ymax))
par(new=new)
plot(x,y,type,lwd=2,col=color,yaxt=yaxis,xaxt=xaxis,ann=ann,ylim=ylim,xlab=xlab,ylab=ylab,xaxs="i",main=main,sub=sub)
abline(0,0)
if(new==FALSE)axis(1,at=seq(lo,hi,sigma))
}

colornormal <- function(lo,hi,color,mu=0,sigma=1,axes=FALSE,ann=FALSE,ymax=0,type="l",new=TRUE)
{
x <- seq(lo,hi,length = 100)
y <- dnorm(x,mu,sigma)
ifelse(ymax==0,ylim<- c(0,dnorm(mu,mu,sigma)), ylim<-c(0,ymax))
par(new=new)
polygon(c(lo,x,hi),c(0,y,0),col=color)
}

## draw normal with label
drawnormal(40,160,"red",100,15,ymax=.028,main=expression(paste("Normal Distribution (",mu == 100,", ",sigma==15,")")),)
colornormal(100,115,"green",100,15)