Box-Cox Transformation

> lambda <- c(seq(-0.9, -0.01, 0.1), seq(0.01, 0.9, 0.1))
> x <- 1:100
> i <- 1
> cols <- rainbow(length(lambda))
> par(mfrow = c(1, 1))
> plot.new()
> for (i in seq_along(lambda)) {
+     par(new = T)
+     y <- (x^lambda[i] - 1)/lambda[i]
+     plot(x, y, col = cols[i], type = "l", xlab = "", ylab = "",
+         ylim = c(0, 20))
+ }
> par(new = T)
> y <- log(x)
> plot(x, y, col = "black", type = "l", lwd = 2, xlab = "", ylab = "",
+     ylim = c(0, 20))
> legend("topleft", legend = lambda, fill = cols, cex = 0.7)