Your question is Experiment Design for a Mobile App. 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).
How would you approach designing an experiment to test a new feature in a mobile app?
Explain how you would define the hypothesis, select a primary metric and guardrails, choose the randomization unit, estimate sample size using an explicit MDE, and determine test duration. Also describe your analysis plan, including peeking, sample ratio mismatch, novelty effects, and the decision rule for shipping.