# Boxplot Example:  US GDP Growth by Party of President
# Chris Adolph

# Load data
data <- read.csv("gdp.csv",na.strings="")
attach(data)

# Construct party specific variables
gdp.dem <- grgdpch[party==-1]
gdp.rep <- grgdpch[party==1]

# Make the histogram
hist(grgdpch,
     breaks=seq(-5,8,1),
     main="Histogram of US GDP Growth, 1951--2000",
     xlab="GDP Growth")

# Make a box plot
boxplot(grgdpch~as.factor(party),
        boxwex=0.3,
        range=0.5,
        names=c("Democratic\n Presidents",
          "Republican\n Presidents"),
        ylab="GDP growth",
        main="Economic performance of partisan governments")