condition mean min max ZT0-3 7.8814166666666665 6.3313299999999995 9.53294 ZT4-7 3.8165750000000003 3.8165750000000003 3.8165750000000003 ZT8-11 3.025945 3.025945 3.025945 ZT12-15 5.2473825 4.345065 6.149699999999999 ZT16-19 5.44028 5.44028 5.44028 ZT20-23 7.669535 7.669535 7.669535