les are described in Table $22\mathrm{.}3$

training set should the dataset into a training set and testing set. The

The testing set should have all observations for $2010,2011,$ and $2012.$

Then, build ins all have all $2014.$

sales $($Elantras a linear regression model to predict monthly Elantra

and CPI.All $Ca{l}_{es}$ Issing Unemployment, Queries, CPI.Energy,

build the model.