Use a simple analogy: "If you flip a coin 10 times and get 7 heads, is the coin biased or were you just lucky? Statistical significance helps us answer that question for business experiments."
Strong answers avoid jargon and use concrete analogies: comparing statistical significance to signal versus noise, explaining confidence levels as "how sure we are this is not a coincidence", and distinguishing statistical significance from practical significance. Best candidates make the concept accessible without oversimplifying.
Tests communication skill, not statistical knowledge. Can they make complex concepts accessible? This is the single most important skill for an analyst working with non-technical stakeholders.