Dear R-users,
I am using R 2.13.0 and rms 3.3-0 , but can not reproduce figure
7.8 of
the handouts *Regression Modeling Strategies* (
http://biostat.mc.vanderbilt.edu/wiki/pub/Main/RmS/course2.pdf) by
the
following code. Could any one help me figure out how to solve this?
setwd('C:/Rharrell')
require(rms)
load('data/counties.sav')
older <- counties$age6574 + counties$age75
label(older) <- '% age >= 65, 1990'
pdensity <- logb(counties$pop.density+1, 10)
label(pdensity) <- 'log 10 of 1992 pop per 1990 miles^2'
counties <- cbind(counties, older, pdensity) # add 2 vars. not in
data
frame
dd <- datadist(counties)
options(datadist='dd')
f <- ols(democrat ~ rcs(pdensity,4) + rcs(pop.change,3) +
rcs(older,3) + crime + rcs(college,5) + rcs(income,4) +
rcs(college,5) %ia% rcs(income,4) +
rcs(farm,3) + rcs(white,5) + rcs(turnout,3), data=counties)
incomes <- seq(22900, 32800, length=4)
show.pts <- function(college.pts, income.pt)
{
s <- abs(income - income.pt) < 1650
# Compute 10th smallest and
10th
largest % college
# educated in counties with
median
family income within
# $1650 of the target income
x <- college[s]
x <- sort(x[!is.na(x)])
n <- length(x)
low <- x[10]; high <- x[n-9]
college.pts >= low & college.pts <= high
}
windows()
plot(Predict(f, college, income=incomes, conf.int=FALSE),
xlim=c(0,35), ylim=c(30,55), lty=1, lwd=c(.25,1.5,3.5,6),
col=c(1,1,2,2), perim=show.pts)