A popular restaurant advertises that it delivers its orders within 30 minutes. Suppose the average delivery time for one store is 27 minutes with a standard deviation of three minutes. One particular order delivery has a z -score of negative 2 point 1 5 Which of the following statements is not a correct interpretation?

A z-score of −2.15 means the delivery time was 2.15 standard deviations below the average. Since the average was 27 minutes and the standard deviation was 3 minutes, the delivery took 27 − (2.15 × 3) = 20.55 minutes, so it was faster, not slower, than average. Therefore, “slower than the average delivery time” is not a correct interpretation.

AI-written and checked against the verified answer.