[R] Normal Curve

[Duncan Murdoch]

On 29/12/2008 4:25 PM, AbouEl-Makarim Aboueissa wrote:
> Dear ALL:
>  
> How I show the area under the normal curve for example for the following example:
>  
> Assume X has N(100,15). How to show the area corresponding to the probability:
>  
>  
> P(90<X<110)
>  
>  
> With many thanks

range <- c(70, 130)
x <- seq(min(range), max(range), len=200)
plot(x, dnorm(x, mean=100, sd=15), type="l")
x <- seq(90, 110, len=100)
y <- dnorm(x, mean=100, sd=15)
polygon(c(x, x[100], x[1]), c(y, 0,0), col="gray")

Duncan Murdoch