a$.$

Month Demand

$145$

$248$

$343$

$448$

$549$

$654$

$747$

$850$

$946$

$1047$

Using the table above, calculate two forecasts using the following method:$-$

i$.$ First, for periods $4$ through $10,$ develop the exponentially smoothed forecasts

using a forecast for period $3($F$3)$ of $45\mathrm{.}0$ and an alpha of $0\mathrm{.}4.[3$ marks$]$

ii$.$ Calculate the weighted moving average for periods $4$ through $10,$ using weights of

$\mathrm{.}70,\mathrm{.}20,$ and $\mathrm{.}10,$ with $0\mathrm{.}70$ applied to the most recent data. $[3$ marks$]$

iii. Calculate the mean absolute deviation $($MAD$)$ for each forecasting procedure.

Which forecasting procedure would you select? Why? $[6$ marks$]$

b$.$

The number of disk drives $($in millions$)$ made at a plant in China during the past $5$ years follows:

Year Disc Drives

$1140$

$2160$

$3190$

$4200$

$5210$

i$.$ Forecast the number of disk drives to be made next year, using linear regression