Please help me answer question $7$ and $9$

$7.$ 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?

$9.$ Consider the sales data for Computer Success given in Problem $7.$

a$.$ Use a $3-$month weighted moving average to forecast the sales for the months April through December. Use weights of $(4/8),(\frac{3}{8}),$ and $(\frac{1}{8},$ giving more weight to more recent data.

b$.$ Use exponential smoothing with $=0\mathrm{.}6$ to forecast the sales for the months April through December. Assume that the initial forecast for January was $$3,200.$ Start error measurement in April.

c$.$ Compare the performance of the two methods by using the mean absolute deviation as the performance criterion, with error measurement beginning in April. Which method would you recommend?

d$.$ Compare the performance of the two methods by using the mean absolute percent error as the performance criterion, with error measurement beginning in April. Which method would you recommend?

e$.$ Compare the performance of the two methods by using the mean squared error as the performance criterion, with error measurement beginning in April. Which method would you recommend?

$10.$ A convenience store recently started to carry a new brand of soft drink. Management is interested in estimating future sales volume to determine whether it should continue to carry the new brand or replace it with another brand. The table below provides the number of cans sold per week. Use both the trend projection with regression and the exponential smoothing $($let $=0\mathrm{.}4$ with an initial forecast for week $1$ of $617)$ methods to forecast demand for week $13.$ Compare these methods by using the mean absolute deviation and mean absolute percent error performance criteria. Does your analysis suggest that sales are trending and if so$,$ by how much?

$\backslash$table$[[$Week$,1,2,3,4,5,6,7,8,9,10,11,12$