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Type 'q()' to quit R. > if(!requireNamespace("lattice") || !requireNamespace("boot")) q() Loading required namespace: lattice Loading required namespace: boot > > ################################################### > ### chunk number 1: setup > ################################################### > options(prompt = "R> ", continue = "+ ", width = 64, + digits = 4, show.signif.stars = FALSE, useFancyQuotes = FALSE) R> R> options(SweaveHooks = list(onefig = function() {par(mfrow = c(1,1))}, + twofig = function() {par(mfrow = c(1,2))}, + threefig = function() {par(mfrow = c(1,3))}, + fourfig = function() {par(mfrow = c(2,2))}, + sixfig = function() {par(mfrow = c(3,2))})) R> R> library("AER") Loading required package: car Loading required package: carData Loading required package: lmtest Loading required package: zoo Attaching package: 'zoo' The following objects are masked from 'package:base': as.Date, as.Date.numeric Loading required package: sandwich Loading required package: survival R> R> suppressWarnings(RNGversion("3.5.0")) R> set.seed(1071) R> R> R> ################################################### R> ### chunk number 2: DGP R> ################################################### R> dgp <- function(nobs = 15, model = c("trend", "dynamic"), + corr = 0, coef = c(0.25, -0.75), sd = 1) + { + model <- match.arg(model) + coef <- rep(coef, length.out = 2) + + err <- as.vector(filter(rnorm(nobs, sd = sd), corr, + method = "recursive")) + if(model == "trend") { + x <- 1:nobs + y <- coef[1] + coef[2] * x + err + } else { + y <- rep(NA, nobs) + y[1] <- coef[1] + err[1] + for(i in 2:nobs) + y[i] <- coef[1] + coef[2] * y[i-1] + err[i] + x <- c(0, y[1:(nobs-1)]) + } + return(data.frame(y = y, x = x)) + } R> R> R> ################################################### R> ### chunk number 3: simpower R> ################################################### R> simpower <- function(nrep = 100, size = 0.05, ...) + { + pval <- matrix(rep(NA, 2 * nrep), ncol = 2) + colnames(pval) <- c("dwtest", "bgtest") + for(i in 1:nrep) { + dat <- dgp(...) + pval[i,1] <- dwtest(y ~ x, data = dat, + alternative = "two.sided")$p.value + pval[i,2] <- bgtest(y ~ x, data = dat)$p.value + } + return(colMeans(pval < size)) + } R> R> R> ################################################### R> ### chunk number 4: simulation-function R> ################################################### R> simulation <- function(corr = c(0, 0.2, 0.4, 0.6, 0.8, + 0.9, 0.95, 0.99), nobs = c(15, 30, 50), + model = c("trend", "dynamic"), ...) + { + prs <- expand.grid(corr = corr, nobs = nobs, model = model) + nprs <- nrow(prs) + + pow <- matrix(rep(NA, 2 * nprs), ncol = 2) + for(i in 1:nprs) pow[i,] <- simpower(corr = prs[i,1], + nobs = prs[i,2], model = as.character(prs[i,3]), ...) + + rval <- rbind(prs, prs) + rval$test <- factor(rep(1:2, c(nprs, nprs)), + labels = c("dwtest", "bgtest")) + rval$power <- c(pow[,1], pow[,2]) + rval$nobs <- factor(rval$nobs) + return(rval) + } R> R> R> ################################################### R> ### chunk number 5: simulation R> ################################################### R> set.seed(123) R> psim <- simulation() R> R> R> ################################################### R> ### chunk number 6: simulation-table R> ################################################### R> tab <- xtabs(power ~ corr + test + model + nobs, data = psim) R> ftable(tab, row.vars = c("model", "nobs", "test"), + col.vars = "corr") corr 0 0.2 0.4 0.6 0.8 0.9 0.95 0.99 model nobs test trend 15 dwtest 0.05 0.10 0.21 0.36 0.55 0.65 0.66 0.62 bgtest 0.07 0.05 0.05 0.10 0.30 0.40 0.41 0.31 30 dwtest 0.09 0.20 0.57 0.80 0.96 1.00 0.96 0.98 bgtest 0.09 0.09 0.37 0.69 0.93 0.99 0.94 0.93 50 dwtest 0.03 0.31 0.76 0.99 1.00 1.00 1.00 1.00 bgtest 0.05 0.23 0.63 0.95 1.00 1.00 1.00 1.00 dynamic 15 dwtest 0.02 0.01 0.00 0.00 0.01 0.03 0.01 0.00 bgtest 0.07 0.04 0.01 0.09 0.14 0.21 0.17 0.26 30 dwtest 0.00 0.01 0.01 0.06 0.00 0.03 0.03 0.19 bgtest 0.05 0.05 0.18 0.39 0.52 0.63 0.64 0.74 50 dwtest 0.02 0.02 0.01 0.03 0.03 0.15 0.39 0.56 bgtest 0.05 0.10 0.36 0.72 0.91 0.90 0.93 0.91 R> R> R> ################################################### R> ### chunk number 7: simulation-visualization R> ################################################### R> library("lattice") R> xyplot(power ~ corr | model + nobs, groups = ~ test, + data = psim, type = "b") R> R> R> ################################################### R> ### chunk number 8: simulation-visualization1 R> ################################################### R> library("lattice") R> trellis.par.set(theme = canonical.theme(color = FALSE)) R> print(xyplot(power ~ corr | model + nobs, groups = ~ test, data = psim, type = "b")) R> R> R> ################################################### R> ### chunk number 9: journals-lm R> ################################################### R> data("Journals") R> journals <- Journals[, c("subs", "price")] R> journals$citeprice <- Journals$price/Journals$citations R> jour_lm <- lm(log(subs) ~ log(citeprice), data = journals) R> R> R> ################################################### R> ### chunk number 10: journals-residuals-based-resampling-unused eval=FALSE R> ################################################### R> ## refit <- function(data, i) { R> ## d <- data R> ## d$subs <- exp(d$fitted + d$res[i]) R> ## coef(lm(log(subs) ~ log(citeprice), data = d)) R> ## } R> R> R> ################################################### R> ### chunk number 11: journals-case-based-resampling R> ################################################### R> refit <- function(data, i) + coef(lm(log(subs) ~ log(citeprice), data = data[i,])) R> R> R> ################################################### R> ### chunk number 12: journals-boot R> ################################################### R> library("boot") Attaching package: 'boot' The following object is masked from 'package:lattice': melanoma The following object is masked from 'package:survival': aml The following object is masked from 'package:car': logit R> set.seed(123) R> jour_boot <- boot(journals, refit, R = 999) R> R> R> ################################################### R> ### chunk number 13: journals-boot-print R> ################################################### R> jour_boot ORDINARY NONPARAMETRIC BOOTSTRAP Call: boot(data = journals, statistic = refit, R = 999) Bootstrap Statistics : original bias std. error t1* 4.7662 -0.0010560 0.05545 t2* -0.5331 -0.0001606 0.03304 R> R> R> ################################################### R> ### chunk number 14: journals-lm-coeftest R> ################################################### R> coeftest(jour_lm) t test of coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 4.7662 0.0559 85.2 <2e-16 log(citeprice) -0.5331 0.0356 -15.0 <2e-16 R> R> R> ################################################### R> ### chunk number 15: journals-boot-ci R> ################################################### R> boot.ci(jour_boot, index = 2, type = "basic") BOOTSTRAP CONFIDENCE INTERVAL CALCULATIONS Based on 999 bootstrap replicates CALL : boot.ci(boot.out = jour_boot, type = "basic", index = 2) Intervals : Level Basic 95% (-0.5952, -0.4665 ) Calculations and Intervals on Original Scale R> R> R> ################################################### R> ### chunk number 16: journals-lm-ci R> ################################################### R> confint(jour_lm, parm = 2) 2.5 % 97.5 % log(citeprice) -0.6033 -0.4628 R> R> R> ################################################### R> ### chunk number 17: ml-loglik R> ################################################### R> data("Equipment", package = "AER") R> R> nlogL <- function(par) { + beta <- par[1:3] + theta <- par[4] + sigma2 <- par[5] + + Y <- with(Equipment, valueadded/firms) + K <- with(Equipment, capital/firms) + L <- with(Equipment, labor/firms) + + rhs <- beta[1] + beta[2] * log(K) + beta[3] * log(L) + lhs <- log(Y) + theta * Y + + rval <- sum(log(1 + theta * Y) - log(Y) + + dnorm(lhs, mean = rhs, sd = sqrt(sigma2), log = TRUE)) + return(-rval) + } R> R> R> ################################################### R> ### chunk number 18: ml-0 R> ################################################### R> fm0 <- lm(log(valueadded/firms) ~ log(capital/firms) + + log(labor/firms), data = Equipment) R> R> R> ################################################### R> ### chunk number 19: ml-0-coef R> ################################################### R> par0 <- as.vector(c(coef(fm0), 0, mean(residuals(fm0)^2))) R> R> R> ################################################### R> ### chunk number 20: ml-optim R> ################################################### R> opt <- optim(par0, nlogL, hessian = TRUE) Warning messages: 1: In log(1 + theta * Y) : NaNs produced 2: In sqrt(sigma2) : NaNs produced R> R> R> ################################################### R> ### chunk number 21: ml-optim-output R> ################################################### R> opt$par [1] 2.91469 0.34998 1.09232 0.10666 0.04275 R> sqrt(diag(solve(opt$hessian)))[1:4] [1] 0.36055 0.09671 0.14079 0.05850 R> -opt$value [1] -8.939 R> R> R> ################################################### R> ### chunk number 22: Sweave eval=FALSE R> ################################################### R> ## Sweave("Sweave-journals.Rnw") R> R> R> ################################################### R> ### chunk number 23: Stangle eval=FALSE R> ################################################### R> ## Stangle("Sweave-journals.Rnw") R> R> R> ################################################### R> ### chunk number 24: texi2dvi eval=FALSE R> ################################################### R> ## texi2dvi("Sweave-journals.tex", pdf = TRUE) R> R> R> ################################################### R> ### chunk number 25: vignette eval=FALSE R> ################################################### R> ## vignette("Sweave-journals", package = "AER") R> R> R> > proc.time() user system elapsed 14.12 0.50 14.60