Sales for the past $12$ months at Computer Success are given here.

$\backslash$table$[[$Month$,$Sales $($$$),$Month,Sales $($$$)],[$January$,3,000,$July,$6,300],[$February$,3,400,$August,$7,200],[$March$,3,700,$September,$6,400],[$April$,4,100,$October,$4,600],[$May$,4,700,$November,$4,200],[$June$,5,700,$December,$3,900]]$

a$.$ Use a three$-$month moving average to forecast the sales for the months May through December.

b$.$ Use a four$-$month moving average to forecast the sales for the months May through December.

c$.$ Compare the performance of the two methods by using the mean absolute deviation as the performance criterion. Which method would you recommend?

d$.$ Compare the performance of the two methods by using the mean absolute percent error as the performance criterion. Which method would you recommend?

e$.$ Compare the performance of the two methods by using the mean squared error as the performance criterion. Which method would you recommend?