#-*- R -*-## Script from Fourth Edition of `Modern Applied Statistics with S'options(echo = T, width=65, digits=5, height=9999)postscript(file="ch01.ps", width=8, height=6, pointsize=9)# Chapter 1   Introduction# 1.1 A quick overview of S2 + 3sqrt(3/4)/(1/3 - 2/pi^2)library(MASS)mean(chem)m <- mean(chem); v <- var(chem)/length(chem)m/sqrt(v)std.dev <- function(x) sqrt(var(x))t.test.p <- function(x, mu=0) {    n <- length(x)    t <- sqrt(n) * (mean(x) - mu) / std.dev(x)    2 * (1 - pt(abs(t), n - 1))}t.stat <- function(x, mu = 0) {   n <- length(x)   t <- sqrt(n) * (mean(x) - mu) / std.dev(x)   list(t = t, p = 2 * (1 - pt(abs(t), n - 1)))}z <- rnorm(300, 1, 2)  # generate 300 N(1, 4) variables.t.stat(z)unlist(t.stat(z, 1))  # test mu=1, compact result# 1.4  An introductory sessionx <- rnorm(1000)y <- rnorm(1000)truehist(c(x,y+3), nbins=25)# ?truehistcontour(dd <- kde2d(x,y))image(dd)x <- seq(1, 20, 0.5)xw <- 1 + x/2y <- x + w*rnorm(x)dum <-  data.frame(x, y, w)dumrm(x, y, w)fm <- lm(y ~ x,  data=dum)summary(fm)fm1 <- lm(y ~ x,  data = dum, weight = 1/w^2)summary(fm1)lrf <-  loess(y ~ x, dum)attach(dum)plot(x, y)lines(spline(x, fitted(lrf)), col = 2)abline(0, 1, lty = 3, col = 3)abline(fm, col = 4)abline(fm1, lty = 4, col = 5)plot(fitted(fm), resid(fm), xlab = "Fitted Values", ylab = "Residuals")qqnorm(resid(fm))qqline(resid(fm))detach()rm(fm,fm1,lrf,dum)hills# S: splom(~ hills)pairs(hills)# S: if(interactive()) brush(hills)attach(hills)plot(dist, time)if(interactive()) identify(dist, time, row.names(hills))abline(lm(time ~ dist))# library(lqs)abline(lqs(time ~ dist), lty=3, col=4)detach()if(interactive()){plot(c(0,1), c(0,1), type="n")xy <- locator(type = "p")abline(lm(y ~ x, xy), col = 4)abline(rlm(y ~ x, xy, method = "MM"), lty = 3, col = 3)abline(lqs(y ~ x, xy), lty = 2, col = 2)rm(xy)}attach(michelson)search()plot(Expt, Speed, main="Speed of Light Data", xlab="Experiment No.")fm <-  aov(Speed ~ Run + Expt)summary(fm)fm0 <- update(fm, . ~ . - Run)anova(fm0, fm)detach()rm(fm, fm0)1 - pf(4.3781, 4, 76)qf(0.95, 4, 76)# End of ch01