The P04_18.xlsx file contains a single-table Data Model on a company’s sales and a single blank worksheet. The goal is to create a pivot table that shows the ratio of average revenue per transaction in the Charleston store to average revenue per transaction in all other stores combined, broken down by month:

a. Create the calculated columns RevenueCharleston:=[Revenue]*(Sales[Store]="Charleston") and RevenueOther:=[Revenue]*(Sales[Store]<>"Charleston"). Then create the measure Ratio1:=Average([RevenueCharleston])/ Average([RevenueOther]) and use it in a pivot table, broken down by month. Explain why you don’t get the desired ratios.

b. Modify the Data Model to get the desired ratios.