## ----echo=FALSE----------------------------------------------------------
library(knitr)
opts_chunk$set(size="small",background="white", highlight=FALSE, cache=TRUE, autdep=TRUE, tidy=TRUE)

## ------------------------------------------------------------------------
bea <-read.csv("http://www.stat.cmu.edu/~cshalizi/mreg/15/lectures/03/bea-2006.csv")

## ------------------------------------------------------------------------
dim(bea)  # Should have 7 columns and 366 rows, and we do
head(bea) # Look at the beginning of the data

## ------------------------------------------------------------------------
bea$gmp <- bea$pcgmp * bea$pop

## ------------------------------------------------------------------------
plot(gmp ~ pop, data=bea, xlab="Population", ylab="Total GMP")

## ------------------------------------------------------------------------
plot(gmp ~ pop, data=bea, xlab="Population", ylab="Total GMP")
abline(a=0,b=4e4)

## ------------------------------------------------------------------------
plot(pcgmp ~ pop, data=bea, xlab="Population", ylab="Per-capita GMP")

## ------------------------------------------------------------------------
plot(pcgmp ~ pop, data=bea, xlab="Population", ylab="Per-capita GMP",
     log="x")

## ------------------------------------------------------------------------
# alter the plotting symbol from a hollow circle to a filled dot (pch)
# shrink the plotting symbols by a factor of 0.5 (cex)
plot(pcgmp ~ pop, data=bea, xlab="Population", ylab="Per-capita GMP",
     pch=19, cex=0.5)

## ------------------------------------------------------------------------
lm(pcgmp ~ pop, data=bea)

## ------------------------------------------------------------------------
plot(pcgmp ~ pop, data=bea, xlab="Population", ylab="Per-capita GMP",
     pch=19, cex=0.5)
abline(lm(pcgmp ~ pop, data=bea), col="blue")

## ----warning=FALSE-------------------------------------------------------
plot(pcgmp ~ pop, data=bea, xlab="Population", ylab="Per-capita GMP",
     pch=19, cex=0.5)
abline(lm(pcgmp ~ pop, data=bea), col="blue")
abline(a=4e4, b=0, col="grey")
abline(a=2e4, b=4e4/2e7, col="green")
lines(smooth.spline(x=bea$pop, y=bea$pcgmp, cv=TRUE), col="orange")