From: Lena Morales, marketing manager at Juniper Lane
Re: Run the spring promotion again?
Lakeside ran 15% off everything for three weeks this spring (promotions.csv: store, start, end, discount). The store team says it was a great success because the store was busy. Before we repeat it, I need to know: did it bring in more revenue, or just more orders at lower prices?
daily_sales.csv has visitors, orders and revenue per store per day. Midtown had no promotion, so use it to see what would have happened anyway. Note that Midtown is closed on Mondays and the odd other day.
Your answer is one of four statements.
A before-and-after comparison on its own can fool you: spring may simply be busier. Comparing with a store that had no promotion over the same weeks takes that out. You'll label the periods, average per open day, compare the two periods with a MultiIndex, subtract the comparison store's change, and decide.