MONTH SALES

Jan $)18,000$

Feb $)20,000$

Mar $)17,000$

Apr $)16,000$

May $)18,000$

Jun $)26,000$

b$.$ Compute the sales forecast for July using the approaches given below. Do not round intermediate calculations. Round your answers to the nearest whole number.

a three$-$month moving average

computers

a weighted three$-$month moving average using $0\mathrm{.}50$ for June, $0\mathrm{.}30$ for May, and $0\mathrm{.}20$ for April

computers

a linear trend equation

computers

exponential smoothing with $a($smoothing constant$)$ equal to $0\mathrm{.}30,$ assuming a February forecast of $18,000$

computers

c$.$ Calculate the MAD for each of the four techniques in part b$.$ Use only the last $3$ months to compare the same number of months for all methods. Do not round

intermediate calculations. Round your answers to the nearest whole number.

MAD $($three$-$month moving average$)$:

computers

MAD $($weighted three$-$month moving average$)$:

computers

MAD $($linear trend equation$)$:

computers

MAD $($exponential smoothing$)$:

computers

Which is the best? Why?