Exercise $10-45$ Static $($Using R$)$

The accompanying data file contains dally sales $($In $\backslash$$$)$ at Caf$$ Venetian for $100$ days. For cross$-$validation, let the training and the validation sets comprise the first $80$ days and the last $20$ days, respectively.

Click here for the Excel Data File

a$.$ Use the training set to Implement the Holt exponential smoothing method with two sets of user$-$supplied smoothing parameters, $\backslash (\backslash$alpha$=0\mathrm{.}20\backslash )$ and $\backslash (\backslash$beta$=0\mathrm{.}10\backslash )$ and $\backslash (\backslash$alpha$=0\mathrm{.}30\backslash )$ and $\backslash (\backslash$beta$=0\mathrm{.}20\backslash ).$ Compute the resulting performance measures for the validation set. Note: Do not round Intermedlate calculatlons. Round "MSE" final answers to the nearest whole number and "MAD", "MAPE" final answers to $2$ decimal places.

b$-1.$ Determine the preferred smoothing parameters for making the forecast?

b$-2.$ Reestimate the preferred model with the entire data set to forecast sales for the $101$st day.

Note: Do not round Intermedlate calculations. Round final answers to $\backslash (\backslash$mathbf$\{2\}\backslash )$ decimal places. $$