Consider the following data on the weekly sales (in $1,000s) at 5 stores of a retail chain, before and after the implementation of a new marketing campaign. The data also appears in the Excel file: Stores Data.xlsx Store 1 2 3 4 5 After 12 13 21 17 15 Before 10 9 18 16 8 Define the change in weekly sales for a store (d;) as the weekly sales after the campaign minus the weekly sales before the campaign. To justify the costs of the campaign, you need to know whether it succeeded in increasing weekly sales on average by more than $1,000. What are your null and research hypotheses?