condition mean min max ZT0-3 3.55858 3.55858 3.55858 ZT4-7 2.5506349999999998 2.5506349999999998 2.5506349999999998 ZT8-11 1.83792 1.83792 1.83792 ZT12-15 2.233595 2.233595 2.233595 ZT16-19 3.04369 3.04369 3.04369 ZT20-23 2.415385 2.415385 2.415385