This is a family of Continuous Distributions
Origin (and usage):
default.par = par() x = seq(-4,4,0.1) n = dnorm(x) library(animation) saveGIF({ par(mar=c(0,0,0,0)) for (i in 1:100) { plot(x, n, type='l', lty=2, col='grey') t = dt(x, df=i) lines(x, t, col='blue') text(1.5, 0.37, paste('df =', i)) text(1.66, 0.35, format(sum(abs(n - t)))) } }, interval=0.1) par(mar=c(0,0,0,0)) plot(x, n, type='l', lty=2, col='grey') for (i in 1:7) { t = dt(x, df=i) lines(x, t, col=i) } par(default.par)