The data for $120$ time periods for a product are provided. Use this data to evaluate the

following prediction methods:

a$.$ A $4-$period moving average, and

b$.$ An exponential smoothing model with a $=0\mathrm{.}1.$ For this model, assume that the

forecast for the first time period is the same as the actual demand for time period

$1.$

Compute the following:

Bias RMSE Period $12$

Forecast

Period $121$

Forecast

$4-$period Moving Average

Exponential Smoothing $(=0\mathrm{.}1)$

$($a$)$ What can you conclude about the two models based on the value of bias?

$($b$)$ Which of the two models would you choose? Why?