Exercise $10-2$ Algo

The accompanying data file contains $20$ observations for $t$ and $y_t.$

Click here for the Excel Data File

a$.$ Use the simple exponential smoothing with $=0\mathrm{.}2$ for making forecasts.

Note: Do not round Intermedlate calculations. Round final answers to $2$ decimal places.

b$.$ Use the in$-$sample forecast errors to compute MSE, MAD, and MAPE.

Note: Do not round Intermedlate calculations. Round final answers to $2$ decimal places.

c$.$ Make a forecast for period $21.$

Note: Do not round Intermedlate calculations. Round final answer to $2$ decimal places.