IN CLASS EXAMPLE $1$: SMA

We will use the following customer$-$arrival data in this example. Table $1$

$\backslash$table$[[$Month$,$Customer arrivals$],[1,800],[2,740],[3,810],[4,790]]$

a$.$ Use a three$-$month moving average to forecast customer arrivals for month $5.$

b$.$ If the actual number of arrivals in month $5$ is $805,$ what is the forecast for month $6?$

c$.$ Given the three$-$month moving average forecast for month $5,$ and the number of patients that actually arrived $(805),$ what is the forecast error?