The Management of Buff Sports Stadium Believes That the Number

The management of Buff Sports Stadium believes that the number of sporting events each month is an measure of activity for total clean-up cost.Shown below are event figures and total clean up costs for the past four months:
Required:
a.Estimate Buff's cost formula for monthly clean-up cost using the high-low method.
b.Estimate Buff's cost formula for monthly clean-up cost using the least-squares regression method.
$\begin{array}{lcc}&\text { Number of } & \text { Total } \\&\text { Sporting } & \text { Clean-up }\\&\text { Events } & \text { Cost }\\ \text { July ........... } & 28 & \$ 30,900 \\\text { August ........ } & 34 & \$ 34,200 \\\text { September..... } & 16 & \$ 20,700 \\\text { October......... } & 22 & \$ 28,200\end{array}$