Welcome to your interview.
The question is on your right: Deciding Signal vs Noise. Take a moment with it first.
Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.
You are reviewing a metric change after a product launch. The team wants to know whether the observed move is real or just noise in the data.
How would you decide whether a metric change is statistically significant or just noise?