Scatter Diagrams and High$-$Low Cost Estimation

From April $1$ through October $31,$ Will County Highway Department hires temporary employees to mow and clean the right$-$of$-$way along county roads. The County Road Commissioner has asked you to help her in

determining the variable labor cost of mowing and cleaning a mile of road. The following information is available regarding current$-$year operations:

Use the information from the high$-$ and low$-$volume months to develop a cost$-$estimating equation for monthly labor costs.

Plot the data on a scatter diagram. Using the information from representative high$-$ and low volume months, use the high$-$low method to develop a cost$-$estimating equation for monthly labor costs.

Adjust the equation developed in requirement $($b$)$ to incorporate the effect of an anticipated $7$ percent increase in wages.