One Key members book 2.3 times as often. How much does One Key cause?
Measure impactHardProblem. A leadership deck says One Key members book 2.3 times as often as non-members, and uses it to argue for richer rewards. You're asked whether that number shows One Key's effect, and if not, how much One Key actually adds.
Before you reveal: say your answer out loud, as if you were in the real interview — get your reasoning across clearly first. There is no single correct answer: reading what the interviewer is really after and defending your own thinking is what makes an answer strong.