# This script plots a binomial likelihood function as a function of x, # and as a function of theta for fixed x. # # Figure caption: Comparison of pdf of f(x|theta) when viewed as # a function of x with theta fixed at 0.5 (on left) or of theta # with x fixed at x = 1 (on right). On the right hand side, the # pdf is evaluated for 99 equally spaced values of theta from 0.01 # to 0.99. # Set graphical device parameters. par(mfrow = c(1, 2)) par(xaxs = "i") # Enables exact specification of plot window. par(yaxs = "i") par(oma = rep(2, 4)) par(mar = c(2, 5, 1, 1)) par(xpd = TRUE) # Plotting clipped to figure region, rather than # plot region. # Set some plotting parameters. point.type <- 16 point.size <- 1.2 label.size <- 1.6 axis.size <- 1.4 # Plot the density evaluated for several possible x values. x.values <- seq(from = 0, to = 4, by = 1) plot(x.values, dbinom(x.values, size = 4, prob = 0.5), xlim = c(0, 4), ylim = c(0, 0.4), pch = point.type, cex = point.size, main = "", xlab = "X", ylab = "PDF", cex.lab = label.size, cex.axis = axis.size) # Plot the density as a function of theta. theta.values <- seq(from = 0.01, to = 1, by = 0.01) plot(theta.values, dbinom(x = 1, size = 4, prob = theta.values), xlim = c(0, 1), ylim = c(0, 0.5), pch = point.type, cex = point.size, main = "", xlab = expression(theta), ylab = "Likelihood", cex.lab = label.size, cex.axis = axis.size) # Close the graphics device. dev.print(device = postscript, "7.2.eps", horizontal = TRUE)