$2.$ a$)$ Given the following historical data, what is the simple three$-$period Moving Average forecast for period $6?$

Period

Actual Value

Period

Actual Value

$1$

$73$

$4$

$72$

$2$

$68$

$5$

$67$

$3$

$65$

b$)$ The following linear equation is used to predict quarterly demand: Yt $=350-2\mathrm{.}5$t$,$ where t $=0$ in the second quarter of last year. Quarterly relatives are as follows: Q$1=1\mathrm{.}5$; Q$2=0\mathrm{.}8$; Q$3=1\mathrm{.}1$; and Q$4=0\mathrm{.}6.$ What is the forecast for the last quarter of this year $?$