Exercises

1. Download Time Series

   • Get the Quandl code for the monthly retailers sales data in millions of dollars, which are not seasonally adjusted, from the Federal Reserve Economic Data database (FRED) either from the Quandl website or the R console.
   • Download all available data for this time series specifying the type argument of the Quandl() function that it matches the recommendation from the stl() help page.

2. Decomposing Time Series

   • Decompose your time series from exercise 1 with stl() function assuming that the seasonal pattern is constant through time.
   • Seasonally adjust the time series and detrend it. This means removing the seasonal component and the trend component from the raw data.