$1$a$.$ Put Purchasing Dept Cost on the Y axis for clarity.

$1$b$.$ Consider the visualizations. Do you notice any outliers and can you explain them with case data? Should you do anything about them $($i$.$e$.$ retain, adjust, or exclude$)?$ Do any potential drivers appear more promising?

$1$c$.$ Run the possible regression combinations $($i$.$e$.$ all potential drivers at once and then each of the possible pairs$).$ Focus on the coefficients and consider what they are telling you. Which is best?

$2$a$.$ What would you tell Joe about cost behaviors at the stores?

$2$b$.$ What recommendations would make?