par(mfrow=c(2,2)) # uniform in the range [-2,+2] n=10000 x.u <- runif(n, -2, 2) y.u <- runif(n, -2, 2) r.u <- sqrt(x.u^2 + y.u^2) # standard norma x.n <- rnorm(n) y.n <- rnorm(n) r.n <- sqrt(x.n^2 + y.n^2) lim = c(-2,2) plot(x.u, y.u, pch=19, cex=0.5, col='blue', xlim=lim, ylim=lim, asp=1) plot(x.n, y.n, pch=19, cex=0.5, col='red', xlim=lim, ylim=lim, asp=1) hist(r.u, nc=50, xlim=c(0,2*sqrt(2)), col='blue') hist(r.n, nc=50, xlim=c(0,2*sqrt(2)), col='red') par(mfrow=c(1,1))