# 1.3 Autocovariances and Autocorrelations

# Plot 1.3.1a: Correlogram of the rst order dierences of the Sunspot Data.
sunspot <- scan("sunspot.txt")
sunspot <- ts(sunspot,start=1749)
plot(sunspot)
acf(diff(sunspot))


# Example 1.3.1. (Airline Data). Plot 1.3.2a, which displays monthly
# totals in thousands of international airline passengers from January
# 1949 to December 1960
airline <- ts(read.table("airline.txt",col.names=c("passangers")),start=c(1949,1),freq=12)
plot(airline)
plot(log(airline))