Question $3[10$ marks$]$

The Instant Paper Clip Office Supply Company sells and delivers office supplies to companies, schools, and agencies within a $50-$mile radius of its warehouse. The office supply business is competitive, and the ability to deliver orders promptly is a big factor in getting new customers and maintaining old ones. $($Offices typically order not when they run low on supplies, but when they completely run out. As a result, they need their orders immediately.$)$ The company manager wants to ensure enough drivers and vehicles are available to deliver orders promptly and have adequate inventory in stock. Therefore, the manager wants to be able to forecast the demand for deliveries during the next month. From the records of previous orders, management has accumulated the following data for the past $5$ months:

$\backslash$table$[[$Month$,$Jun.,Jul.,Aug,Sept.,Oct.$],[$Order$,50,75,130,110,90]]$

A$.$ Compute the monthly demand forecast for July through November using the naive method. $[2$ mark$]$

B$.$ Determine the monthly demand forecast for September through November using a $3-$month moving average. $[2$ mark$]$

C$.$ Calculate the monthly demand forecast for September through November using a $3-$month weighted moving average. $[2$ mark$]$

D$.$ Determine the mean absolute deviation $($MAD$)$ and Mean Square Error $($MSE$)$ for September and October for each method used. $[2$ mark$]$

E$.$ Explain which method would you use to forecast demand for November and why. $[2$ mark$]$