condition mean min max ZT0-3 3.427486666666667 2.662795 3.8529400000000003 ZT4-7 3.770485 3.770485 3.770485 ZT8-11 4.73494 4.73494 4.73494 ZT12-15 6.994495000000001 6.499365 7.489625 ZT16-19 6.3256049999999995 6.3256049999999995 6.3256049999999995 ZT20-23 5.497605 5.497605 5.497605