PROBLEM IV$.$ The number of items sold over a six$-$month period are:

$\backslash$table$[[$month: $1,2,3,4,5,6],[$sales: $4410,4540,4520,4480,4390,4530]]$

Calculate the forecast for the $4$ th$,5$ th$,6$ th and $7$ th months using $3-$month simple moving average, and $3-$month weighted moving average with weights of $0\mathrm{.}5$ for the most recent month and $0\mathrm{.}3$ for the month preceding the most recent month.

$(15)$ Under the $3-$month Simple Moving Average Method, the forecast for the $5^{th}$ month is:

$($a$)4490$

$($b$)4513\mathrm{.}33$

$($c$)4543\mathrm{.}33$

$($d$)4556\mathrm{.}18$

$($e$)$ none of the above

$(16)$ Under the $3-$month Simple Moving Average Method, the forecast for the $7^{th}$ month is:

$($a$)4458$

$($b$)4525$

$($c$)4484\mathrm{.}24$

$($d$)4466\mathrm{.}67$

$($e$)$ none of the above

$(17)$ Under the $3-$month Weighted Moving Average Method, the forecast for the $6^{th}$ month is:

$($a$)4443$

$($b$)4512$

$($c$)4563$

$($d$)4457$

$($e$)$ none of the above

$(18)$ Under the $3-$month Weighted Moving Average Method, the forecast for the $7^{th}$ month is:

$($a$)4497$

$($b$)4532$

$($c$)4478$

$($d$)4576$

$($e$)$ none of the above