Grafico prodotto con R e successivamente manipolato con GIMP:

filename <- function(name="",ext="png",dir="./statistica/") {
    paste(dir,"Grafico_v.c.",name,".",ext,sep="")
}


#####################################################
# Gaussiana
name <- "Gaussiana"

par(mai=c(0,0,0,0))
png(file=filename(name),width=640)
minX <- -4
maxX <-  4
curve(dnorm,
      minX,maxX,
      ylab="",xlab="",
      ylim=c(0,dnorm(0)*1.1),
      xlim=c(minX,maxX*1.1),
      axes=FALSE,
      )
arrows(minX,0,maxX*1.09,0)
arrows(0,-dnorm(0)*0.01,0,dnorm(0)*1.09)
lim <- -1.96
vals <- seq(minX,lim, length=100)
x <- c(minX, vals, lim, minX)
y <- c(0,dnorm(vals),0,0)
polygon(x,y,density=20, angle=45)
text(lim,-dnorm(0)*0.01,lim,adj=c(0.5,1))
arrows(-2.7,0.07,-2.4,0.03)
text(-2.9,0.09,"2,5%")
text(0,-dnorm(0)*0.01,"µ=0",adj=c(0.5,1))
text(1,-dnorm(0)*0.01,expression(sigma==1),adj=c(0.5,1))
text(2.1,0.35,expression(f(x)==frac(1,sigma*sqrt(2*pi))*e^{-(x-µ)^2/(2*sigma^2)}),cex=1.5)
lines(c(1,1),c(0,dnorm(1)),lty=3)
dev.off()