karlin2.R

x <- seq(-3,  3, length.out = 100)
{ dnorm(x, 2, 1) / dnorm(x, 1, 1) ~ x } %>% 
  xyplot(
    col = 'black', type = 'l', lwd = 2, ylim = c(-.6, 4.8),
    ylab = expression(paste('f(x', '|', theta[1], ')', ' / ', 'f(x', '|', theta[0], ')')),
    panel = function (x, y, ...) {
      panel.grid(h = -1, v = -1)
      panel.xyplot(x, y, ...)
      panel.abline(h = 0, lty = 2)
      panel.segments(0, dnorm(2, 2, 1) / dnorm(2, 1, 1), 
                     2, dnorm(2, 2, 1) / dnorm(2, 1, 1), lty = 2)
      panel.text(0.5, dnorm(2.1, 2, 1) / dnorm(2.1, 1, 1), labels = c('Assumed k'))
      
      from.z <- 2
      to.z <- 3
      S.x  <- c(from.z, seq(from.z, to.z, 0.01), to.z)
      S.y  <- c(0, dnorm(seq(from.z, to.z, 0.01), 2, 1) / dnorm(seq(from.z, to.z, 0.01), 1, 1), 0)
      
      panel.polygon(S.x, S.y, col = 'gray', border = 'white')
      panel.segments(2, dnorm(2, 2, 1) / dnorm(2, 1, 1), 2, 0)
      panel.segments(2, 0, 3, 0)
      panel.segments(3, dnorm(3, 2, 1) / dnorm(3, 1, 1), 3, 0)
      panel.curve(dnorm(x, 2, 1) / dnorm(x, 1, 1), 2, 3, lty = 2, lwd = 2)
      panel.text(2.5, 1, labels = expression(T >= t[0]))
      panel.text(2, -.2, labels = expression(t[0]))
      panel.arrows(2.45, dnorm(2.5, 2, 1) / dnorm(2.5, 1, 1), 1.7, 2.9, angle = 20)
      panel.text(1.3, 3, labels = expression(lambda(x) > k))
    }
  )