Compute a three$-$quarter moving average forecast for quarters $4$ through $13$ and

compute the forecast error for each quarter.

b$.$ b$.$ Compute a five$-$quarter moving average forecast for quarters $6$ through $13$ and

compute the forecast error for each quarter.

c$.$ Compute a weighted three$-$quarter moving average forecast using weights of $0\mathrm{.}50,$

$0\mathrm{.}33,$ and $0\mathrm{.}17$ for the most recent, next recent, and