$(20\%)$ Assume last year$$s $(2019)$ monthly sales figures for a business were:

January $95,000$ May $147,000$ September $152,000$

February $105,000$ June $169,000$ October $140,000$

March $134,000$ July $184,000$ November $134,000$

April $118,000$ August $177,000$ December $129,000$

Based on the sales figures above, show the monthly forecast for the same year $(2019)$ along

with the January forecast for the next year $(2020)$ for each of the forecasting methods below.

In addition, determine and state which of the three is the preferred forecasting method for your

company by calculating the Mean Absolute Deviation $($MAD$)$ for each.

a$.4-$month moving average

b$.$ Weighted moving average $($weights of $\mathrm{.}4,\mathrm{.}3$ and $\mathrm{.}3)$

c$.$ Exponential smoothing $($alpha $=\mathrm{.}2,$ assumed forecast for January $2019$ of $$90,000)$