Step-by-step explanation: To solve this, you need to do the z-score formula with both numbers. So 30-22/2.5 = 3.2. On the z-score chart, that equals .9993. Hold onto that number. Then you do the same with 15. 15-22/2.5 = -2.8. On the z score chart, that equals .0026. Subtract those numbers. .9993 - .0026 = .9967. It's not as compacted as it looks <3
