#   Plots of Binomial distributions

plot.binomial <- function(panel) {
   with(panel, {
      dev.set(dev.number)
      n <- as.numeric(n)
      probs <- dbinom(0:n, n, prob)
      plot(c(0,n), c(0,1), type = "n", xlab = "x", ylab = "Probability")
      segments(0:n, rep(0, n+1), 0:n, probs)
      title(paste("Binomial:  n =", n, "  p =", round(prob, 3)))
      })
   panel
   }

rp.binomial <- function() {
   x11(width = 3, height = 3)
   pname <- rp.control("Binomial probabilities", n = 20, prob = 0.5, dev.number = dev.cur())
   rp.slider(pname, prob, 0, 1, initval = 0.5, title = "Binomial proby, p:", 
                   action = plot.binomial)
   rp.textentry(pname, n, plot.binomial, "Sample size, n:")
   }

rp.binomial()