Your question is Campaign Lift Test for Sales. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
You work on a consumer goods business that is considering a new campaign to drive sales. Early results suggest sales may be up, but the team is unsure whether the change is causal or just noise from normal demand swings.
How would you test whether the campaign caused an increase in sales? Explain how you would define success, choose the randomization unit, and decide whether the result is strong enough to ship.